"I think Kamen Rider 1 would work well with any hero. As long as the stories foster hopes and dreams for children and the heroes share a general objective, there are no limits to the possible team ups." -Hiroshi Fujioka, voice actor for Takeshi Hongo/Kamen Rider 1.

An awesome quote and I would like to believe it could apply to any Kamen Rider.

Hello everyone. This is a one-shot crossover between Ben 10 and the Kamen Rider franchise. Specifically one of my favorite Kamen Riders of all time: Kamen Rider W/Double. Enjoy.

I didn't send this to my pals Vandenbz or Pyromania to proofread because this is just a two-shot story and both chapters came out much longer than I intended, so I wasn't going to dump so much work onto them.

Disclaimer: Ben 10 and Kamen Rider do not belong to me.

Ben 10: Futo Adventures

Part 1

Futo; a city in Japan that certainly lived up to its name "Windy City", especially with its prominent windmill towers. The newcomer walking through the streets took a moment to take them in. He was an American, sixteen years old with brown hair and bright green eyes. He wore blue jeans and a green jacket over a solid black shirt. Draped over his shoulder was a black duffel bag and he was holding a brown suit case in his right hand.

His name was Ben Tennyson.

"Wow, Gwen wasn't kidding about this place," Ben said to himself in English as he noticed the various windmills, pinwheels, whirligigs, and windchimes scattered all over the place. "This has got to be the most eco-friendly city in the entire world. Still pretty cool though."

Ben noticed the polite and friendly way everyone seemed to greet each other even in passing. Despite having just arrived, Ben could feel as if his body was being filled with positive energy just by being here. Smiling he put his suitcase down, reached into his pocket and pulled out a folded, white sheet of paper.

"Okay," he said as he began unfolding it. "How do I find the Narumi Detective Agency again?"

"Um, excuse me?"

Ben lifted his head to see a young woman looking at him with a tilt of her own. She wore orange shorts and a short sleeved, light pink hoodie over a yellow t-shirt. Her black hair was tied in a ponytail, a brown jacket draped over her left arm and a white satchel with various designs draped over her shoulder.

"Did you just say the Narumi Detective Agency?" All this, just as her previous question, was all in Japanese.

"Yes I did" Ben replied in Japanese "Would you happen to know where it is?"

The girl smiled as she held up a piece of paper. "I'm heading there myself. Do you want to come with me?"

"Yes, thank you," Ben said gratefully, picking up his suitcase again.

"You're welcome," The girl said pleasantly as she held out her hand. "Oh, I'm Narumi Akiko."

"Tennyson, Ben" Ben said in turn, shaking her hand as he remembered that people introduced themselves by their family name first in Japan. As he did so, he couldn't help noticing her lack of reaction to his name. "So does that mean…"

"The agency belongs to my father, Narumi Sokichi," Akiko replied before lowering her head. "But—I haven't seen him in a long time."

Ben cringed. "Sorry."

Akiko's smile returned. "It's okay. Maybe he'll be in the office and I can surprise him."

"Err, if that's the case, I can come by at a later time," Ben offered. "I wouldn't want to get in the way of a family reunion."

"Well, do you have a case for my father?" Akiko inquired curiously.

Ben scratched his left cheek. "Something like that."

"Then it's settled!" Akiko said, suddenly grabbing Ben's arm and yanking him down the road.

"Hey, what-" was all Ben could say as Akiko essentially dragged him along, grunting as his suitcase occasionally bumped against his legs.

Unbeknownst to them, a man had been watching the entire spectacle in amusement and intrigue. He wore a black business suit and a white scarf sporting a great, red blotch. His hair was neatly combed to the right, the tips of his longest bangs somewhat obscuring his eye. Originally the man had just been pleased to see that a tourist, especially an American one, had been impressed by his wonderful home. What really caught his attention, however, was when the boy introduced himself.

Ben 10. What sort of wind had brought the likes of him to Futo?

Adjusting his suit, the man turned around and started walking away. He would have to inform his superiors of this unexpected development. He smiled as he suspected they wouldn't be too bothered about the American hero in their city. After all, he had actually been a boon to their business, even if said hero was completely unaware of it.

/*/

"Oh, you really came all the way from America?" Akiko asked in wonder.

Ben grinned. "Sure did."

"Your Japanese is actually pretty good," Akiko said, impressed.

"Thanks but I can't take the credit," Ben said with a smile. "My grandpa and cousin were the ones who made sure I got it down-packed. That and I watched a lot ofanime with subtitles to practice with." He added, rubbing the back of his head with a sheepish smile.

"Oh, we're here!" Akiko exclaimed, pointing to a rectangular building.

In the sign on top of the building, between the words Kamome and Billards were two pool sticks criss-crossing each other. Above the sticks was the 8 ball and below was the 3 ball. The 9 ball was to the far left and the 2 ball on the far right. On the roof of the building were some more wind ornaments. One was a pair of red, half spheres like cups that spun in a circle while the other three were bird-shaped whirligigs, their wings spinning like propellers. Akiko then went over to a smaller door to the left of the hall's twin door entrance. Ben was about to join her when he heard the sound of tires coming to a halt behind them. He turned to see a unique motorcycle had parked.

He was no expert on vehicles like Kevin was but if he had to make a guess, he'd say it was a customized Honda. The back of the vehicle was green while the front was black. The driver wore black dress shoes and pants, a black vest over a white dress shirt with black, vertical stripes, and a red necktie. Taking off his helmet to reveal messy black hair and brown eyes, the man reached over on his left and pulled out a black fedora. Taking a moment to brush his hair out of the way, he placed the fedora on his head and gave the two a suspicious look and said evenly.

"Do you…have business with me?"

Akiko turned towards him and, giving her lack of reaction to him, the man was not her father. A partner perhaps?

"What does hard-boiled mean?" she asked, pointing towards the door.

Curious, Ben turned towards the door, noticing a wooden plaque next to it. Narumi Detective Agency was what the plaque read. Attached to the bottom was what appeared to be a piece of cardboard. Written on the cardboard were the words Solving all cases with a hard-boiled style!

Ben raised a brow at the sign.

/*/

The man led Akiko and Ben to the second floor of the building, leading them to a large room. The first half of the room was painted green. To the right was a coat rack of which hung multiple fedoras, a radio, a dart board, and a pool table. To the left was an assortment of furniture such as several chairs, a couch, and a coffee table. Past the archway, the other half of the room was mainly white. There was a kitchen, a small table where the motorcyclist put his helmet down, and a desk at the far corner.

The man went over a bookshelf across from the desk and selected a large paperback out of it. "Not being swayed no matter what the situation. It's a man-among men's lifestyle,"

He sat at the desk and placed the book down in front of Akiko. Ben looked over her shoulder to see the cover had a revolver beside the English title The Long Goodbye.

"That is," the man ran a finger along the brim of his fedora as he looked at Akiko coolly. "Hard….boiled."

Ben tried to keep a straight face at the man's obvious cool guy routine but Akiko was not so subtle. She plopped her jacket onto the man's desk unceremoniously before placing her backpack onto it as well. Scrunching his face in annoyance, the man picked up a pristine coffee cup as Akiko rummaged through her bag. No sooner had he taken a swig when Akiko produced a piece of paper.

"I'm evicting you," She held up the paper. "Here's my registration."

Ben did a double take as the self-proclaimed "hardboiled" man spat his coffee out. Taking off his fedora as he struggled to catch his breath, the man stood up. "What?!" He cried the moment he could speak.

Nonplussed by his reaction, Akiko put the document down and turned, looking the room/office over. "I'm this place's landlord now so please leave, you strange wannabe detective."

Gawking at being called a "wannabe detective" the man started to follow Akiko before turning around and grabbing the paper. Unable to help himself, Ben looked over his shoulder. It was a document and from what Ben was reading, it certainly looked official. The detective looked over the document up and down, even sniffing the paper to test its authenticity. Scoffing, he turned towards Akiko, Ben quickly moving out of his way.

"What a naughty girl," The man said in bemusement as Akiko turned around to face him. "A neighborhood middle schooler shouldn't be messing around in my hard world."

Akiko harrumped as she stood in front of him. "I just came to this city. Plus I'm not a middle schooler, I'm twenty!"

Ben and the detective both blinked in surprise at this. Ben had assumed she was the same age as him. "No way," The detective said, taking a step back as he looked Akiko over.

Ben rubbed his head, feeling really out of place right now. "Um, hey Akiko," as the other two occupants brough their attention to him, Ben took a breath. "I thought you were here to visit your father."

The detective looked back at Akiko. "Father?"

"I'm Narumi Akiko, this is my father's agency."

The detective's eyes widened. "The boss' daughter?"

So he knew Narumi at least and judging from how he addressed him as "Boss" Ben suspected the man was an apprentice. Then he noticed the melancholy look on the detective's face as he lowered his head.

"Boss is–" He walked over to the coat rack and Ben noticed his eyes lingered on the uppermost fedora; a white one with a slight tear in the edge of the brim. "Boss is–for now—not returning."

"I didn't hear anything about that," Akiko said, walking up to the detective again.

Ben frowned as he folded his arms, already suspecting what the detective actually meant, especially with how he was looking away from Akiko. "Boss is—for me–"

Since this was obviously extremely personal and private, Ben meant to wait outside when the doorbell rang. "Saved by the bell," He said to himself as the detective went to open the door. Standing before him was a woman in a blue dress with white sleeves and collar. Her hair was neatly tied behind her. She smiled at the detective, looking at him with relief and hope.

"Sho-chan," she said softly. "It's been a while."

The detective studied her a moment before his eyes widened in recognition. "Marina!" He exclaimed happily.

The woman, now named Marina, nodded in response but her smile soon fell to worry.

/*/

Marina was now sitting in front of the detective's desk. She had placed a photo, which the detective was now looking over. Aside from Marinah herself, there was a man with his arm around her. The two of them were smiling as the picture was taken.

"Togawa Yousuke," The detective said before looking back at Marina. "Your boyfriend?"

Marina nodded, letting out a shaky breath. "He's disappeared," The poor woman sounded close to tears. "For over a week already." She looked up at the detective desperately. "Please find him for me!"

Ben rubbed the back of his neck, sitting in a big red chair back in the green side of the room. He felt so out of place right now. The detective placed the photo back on his desk and stood up, removing his hat from on top of an old rotary dial phone.

"The city is my garden," the detective said firmly, nodding at Marina. "Don't worry, I'll find him."

Marina smiled again, nodding in gratitude.

/*/

"My name is Hidari Shotaro; private eye. The city contains a lot of happiness but also a lot of sorrow. It always comes in with the wind. A request from my childhood friend, Tsumura Marina…was truly a gust of wind dropping by."

"Are…are you seriously narrating to yourself?"

Shotaro, who had been leaning against a lampost with his head bowed, looked up. "Huh?"

Ben was about to respond when Akiko beat him to the punch. Or rather the green slipper. That's right, Akiko had pulled a green slipper out of a yellow and green bag draped across her shoulder and conked Shotaro upside the head with an audible BONK! The detective staggered for a moment in pain and shock before rounding on Akiko as she stuffed the slipper back into her bag.

"You!" He growled then spotted Ben standing a few feet away from them. "You two were following me?!"

"Sorry about that," Ben said sincerely.

"I'm not," Akiko said, folding her arms. "I'm still judging this guy."

"Why?" Ben inquired. "So far from what I've seen, he's doing great. It was thanks to him we learned Togawa's disappearance might be connected to his job laying him off."

Shotaro nodded in approval as he spent the time asking around the city for anyone who might know Yousuke Togawa. "Thank you. See, your boyfriend gets it."

"We're not a couple!" Akiko shouted at him, looking ready to dig back into her bag. "We just met today!"

"And I already have a girlfriend," Ben added, not to mention the age difference between him and Akiko.

Shotaro looked at them quizzically before focusing his attention on Ben. "The two of you just met today?"

"That's what I said," Akiko said, then she blinked as something dawned on her. "By the way, Ben. Why were you looking for the agency?"

"You're asking him that now?" Shotaro said incredulously.

"You didn't ask him either!" Akiko pointed out.

"I thought the two of you were together!" Shotaro argued.

"To be fair," Ben spoke up. "A lot of stuff happened almost right after we met you, so I was gonna wait until this case was settled. As for why I followed you, well I wanted to see if I could help. I'm no detective but I've got some experience."

"Hmm," Shotaro put his hands on his hips. "I appreciate the thought but…" Ben was about to ask what was wrong when he heard the blaring of sirens.

Ben, Shotaro, and Akiko were staring at a traffic jam that led into a smoking tunnel. Police cars and ambulances parked on the other side of the road; medics pushing gurneys into the tunnel while officers were escorting panicked but otherwise unharmed people out of the tunnel. Other drivers caught in the traffic jam were sticking their heads out, trying to figure out what was going on. Ben immediately dashed towards the tunnel, starting to roll up his left sleeve when a hand clamped onto his shoulder. He spun around to see Shotaro shaking his head, Akiko standing behind him.

He pointed to the left and Ben saw officers trying to deter other curious civilians. Shotaro crouched down next to a car they had been standing beside, Ben and Akiko following his lead. Looking over the car to make sure they hadn't been spotted, he nodded and pointed forward. Akiko and Ben nodded back before all three began duck walking towards the tunnel, keeping as close to the line of cars as possible. Not the most gracious way of stealth but it was necessary. As the trio passed a limousine that had been stuck in the traffic, the back door opened.

Out stepped a beautiful young woman in a white and red dress, her hair neatly tied into stylized buns on either side of her head. She had no concern for the three comically trying to sneak their way into the tunnel. Once they were close enough, the three stood back up and ran into the tunnel.

"It stinks," She said to herself at the lingering smoke before grimacing. "Tch."

/*/

Ben winced as he along with Shotaro and Akiko ducked and weaved past the officers, medics, and fire fighters, a few lingering civilians trying to get out of the tunnel as soon as possible. As the three passed a fire truck, Ben came to a halt, nearly causing Shotaro and Akiko to knock into him. The sight before them made them all gasp.

"Is that—part of a building?!"

Shotaro nodded grimly. "A building collapsed on the tunnel."

"A bomb?"

"Hard to say," Shotaro walked over to some of the rubble. Ben followed him and noticed that there were English letters on some of th stone. The ones he could make out the most was ALE. Shotaro took off his hat and turned it to the left. Ben noticed that his fedora sported a logo: WINDSCALE.

"Windscale," Shotaro read aloud, putting his fedora back on his head as he pulled out Togawa's photo. "This was where Togawa used to work."

"Hey, detective!"

Ben, who had just about to comment on a possible connection, flinched as a man with short, somewhat spiky hair stomped towards Shotaro and grabbed him by the tie. "Why are you sticking your nose in police business again?!"

Shotaro just grinned as he pushed the man's hand off his neck, grabbing him by the shoulders. "Ah, Makura. I have no time to deal with a detective underling."

He started to walk away before Makura stomped towards him and grabbed him by his vest. "What was that?! Stop being so full of yourself!"

"Hey now," Shotaro said coolly. "No need to be so antagonistic."

Ben just started as the two verbally went back and forth. It reminded him of those noir stories where the P.I. was on bad terms with the police.

"Stop it!" Another man in a gray suit with an open jacket shouted, causing Shotaro and Makura to instantly cease. He looked at them both in disapproval. "You two are going at it like a dog and a monkey."

Ben tilted his head, making sure he heard that right. Monkeys and dogs didn't get along? Huh. You learned something new everyday.

"Shotaro, come with me," the new man said, wrapping what appeared to be a plastic, cane-shaped back scratcher on Shotaro's shoulder and pulling him towards the rubble. Makura continued glaring at Shotaro as Ben and Akiko followed the two.

"Sorry about that, Jinno-san," Shotaro said respectively.

Jinno just waved it off, smiling at Shotaro. "Your nose was on the mark again, Shotaro." He pointed at the rubble with his back-scratcher. "See that? That's the fourth floor of the Windscale building."

Shotaro pulled out a bulky, bluish camera and started taking pictures. Ben looked over the wreckage dismally, He could only imagine how many people had been hurt…and worse because of this.

"The only way that could've happened would be if the steel floor in the foundation was melted."

Ben studied the rubble. Melted? Sure Heatblast or NRG could do that no problem but what else could be hot enough to—

"So it's a Dopant?"

Ben turned towards Shotaro, who had stopped taking pictures and now had a grave expression on his face.

"Dopant?" Ben and Akiko asked simultaneously, the latter leaning up to Shotaro to where her chin nearly touched his shoulder.

"Yeah," Jinno said as he scratched his shoulder. "Including last week this makes the count up to three. First time it was this bad though."

Ben's eyes widened. Three?

After looking back and forth, Jinno reached into his jacket and pulled out an envelope. "Let me know if you find anything," he said as he handed it to Shotaro before walking back to his fellow officers.

Shotaro took one look at the envelope before quickly tucking into his vest. Akiko, who had been trying to sneak a peek at the envelope, pouted in annoyance. Ben just took another look at the destruction. Just who or what was a Dopant? And was it possibly the reason for him needing to be here?

/*/

Once they were out of the tunnel, Shotaro opened the envelope and pulled out several pictures. Leaning against the wall to the tunnel entrance, he began looking through them. Ben stood beside Shotaro while Akiko was, for some reason, looking down at them from the sidewalk leading to the tunnel bridge. Each picture showed devastation and casualties, no doubt from the mysterious Dopant's previous attacks. "So they were all branches of the company that Togawa worked at huh?"

"Shot in the dark but I'm guessing you think he might be involved in this?" Ben asked.

"Most likely," Shotaro said, shaking his head. "This started out a search for a missing person, but now it involves a Dopant."

"Dopant?" Akiko asked again.

Shotaro looked at her but promptly ignored her question. "Looks like we're up," He sighed in an almost theatrical manner. "Such is the whim of the wind."

BONK!

Ben didn't have enough time to warn Shotaro when Akiko's green slipper conked him over the head again. Leaning down, she grabbed Shotaro by the head as if to twist his neck.

"Quit with the tough guy act!" She yelled. "Hurry up and tell me what a Dopant is!"

"Kinda hard for him to explain when he's in pain, Akiko," Ben pointed out, cringing at her.

"Exactly!" Shotaro shouted. "Don't use violence!"

A ringing sound came from Shotaro's pocket, halting Akiko's assault on the detective. Shotaro quickly pulled out a bulky, black flip phone and answered. "Ah, Philip."

"Philip?" Akiko asked, releasing Shotaro.

"Did you get the pictures I sent you?" Shotaro asked as he straightened out his neck.

"A contact?" Ben wondered aloud.

"Fascinating," A young male's voice said over the phone. "It's very compelling."

Shotaro rolled his eyes as Akiko made her way to them, trying to get more answers. The detective held out his arm to keep her at bay. "I need to know about the Dopant's powers. Look up his Gaia Memory."

"Gaia Memory?" Ben repeated.

Then as Shotaro turned, looking into the tunnel, he froze. "Actually, never mind," He said tensely.

"Why not?" The mysterious Philip asked in confusion.

"Because he's standing right in front of me,"

Ben's head shot toward the tunnel, his eyes landed on an orange glow that seemed to be getting brighter and closer. Then his eyes widened as the source of the glow came into view. It had the body of a humanoid male, his skin colored like blackened stone. The orange light not only came from cracks along his body but also flames that mostly formed around his head and shoulders. The ground beneath his feet had melted into pools of lava. While not identical, the strange creature reminded Ben slightly of Heatblast. Hastily he rolled his sleeve as Shotaro pushed Akiko behind him.

"His memory's name is—" Shotaro put down the phone. "Magma."

The creature let out a roar, his flames intensifying like an aura around him.

"Run!" Shotaro yelled, grabbing Akiko.

The creature roared again, sending a blast of flames and a steam of lava that obliterated the ground in front of him. Before the fire or lava could touch the three, there was a flash of green light but it was almost instantly blocked out by the inferno created by the monster's attack. When the flames died down there was an entire line of lava leading up to the main road. The monster looked around and, seeing no sign of the three humans, turned around and ventured deeper into the tunnel.

If the monster had bothered to look up, it would have seen Akiko and Shotaro, both slightly in a daze, as they were held in the arms of what appeared to be a blue moth man with four wings. His body was black with patches of cyan on his limbs and shoulders that looked like a cross between chunks of ice and armor. His torso sported three plates on his torso, resembling his chest and stomach. His slightly skull-like head had large green eyes, blue cheeks, and bluish white teeth. On his chest was a green symbol that vaguely resembled an hourglass.

"So," the moth creature said in a low voice like a whisper. "I'm guessing that was a Dopant?"

Shotaro shook his head, everything had been such a blur when the monster had attacked. Then he looked up and his eyes bulged as he saw their rescuer. Anything he was about to say was cut off by Akiko's piercing scream.

"Monster!" She began thrashing wildly, digging into her bag.

"Akiko, wait…"

BONK!

"Begone demon!"

BONK! BONK! BONK! BONK!

The young woman had pulled out her slipper and started whacking the moth man as hard as she could. Said moth man fluttered back and forth in agitation.

"Oi!" Shotaro shouted, trying to wrestle the slipper from her as he felt the moth creature's arms slacking. "Not while he's holding us in mid-air!"

Wincing as Akiko continued to smack him, the moth creature flew to the bridge and, as best he could, gently set the two down. Once he did he wrapped his wings and large antenna around him, making him look more like a robed ghost. Akiko went to smack him one more time but this time, much to her shock, she went through him, letting out a squeal as she tumbled onto the concrete. Shotaro gawked as the moth man's body had become transparent.

"Sorry but that was getting kind of annoying," The moth man was engulfed by a flash of green light. Akiko turned away the same time Shotaro held his hat out to shield his eyes. Once the light disappeared, both looked to see Ben standing in the moth man's place, rubbing his head.

"You got me good, Akiko," He said with a wince. "Anybody got some aspirin?"

"EH?! Ben was the moth monster?" Akiko grabbed her own head. "I didn't hear anything about this! What is going on in this city?!"

"That's what I want to know," Shotaro stood in front of him, eyes narrowed. "What was that you just turned into? Was that a Dopant too? Do you have a Gaia Memory?"

"No, unless Dopant is what you call aliens around here."

Shotaro took a step back as Akiko's jaw dropped. "Eh? Aliens?"

"You guys really don't know anything about me, huh?" Ben folded his arms. "Guess I'm not that well known outside of America after all."

Suddenly Akiko grabbed him by the jacket and started shaking him. "Your turn now! Start explaining!"

"I will! I will! Calm down!" Ben yelled, causing Akiko to release him. Straightening out his jacket, Ben rolled up his sleeve once again. Shotaro and Akiko stared at what appeared to be a green gauntlet with a black rectangular button and wrist couplings. Its interface screen resembled the symbol that had appeared on the moth creature's chest.

"This is called the Ultimatrix and it lets me turn into different aliens," Ben explained. "I call the one you just saw me as Big Chill."

"Big Chill?" Akiko repeated. Finally she let out a cry. "Dopants, aliens, Ulti-whatever!" She turned and ran.

"Akiko, wait!"

"Let her go," Shotaro said, hands in his pockets as Akiko ran without looking back. "That middle schooler is probably going back to her hometown. It's better for her sake if she does so."

"Still," Ben, also putting his hands in his pockets. "I wasn't trying to drive her away. I guess I'm so used to everyone knowing who I am."

"Maybe," Shotaro said. He stood in front of Ben. "You're famous in America huh?"

Ben nodded. "Yeah I'm uh, well basically I'm a superhero."

"A superhero? I guess you can turn into other things besides that Big Chill mothman?"

Ben grinned a little. "A lot more."

Shotaro scratched his chin. "I see. But what I really want to know is, what is an American superhero doing all the way in Futo?"

"Sure you don't want to wait until your case is solved?" Ben asked. "That Magma Dopant monster is still out there. We stop him first and then I'll tell you everything I know."

Shotaro tilted his head. "We?"

"Please," Ben said softly. "I know this isn't my city but that Dopant guy has obviously hurt a lot of people and I can help stop him. He's dangerous but I've faced things way worse than him."

Shotaro folded his arms as he looked Ben over. Next he looked into Ben's eyes. He could see the determination and eagerness to help.

"It's not my usual style but that Dopant is making my city cry. If you're serious about wanting to help stop him, you're on."

Ben smiled. "Thanks, Detective Hidari.

Shotaro returned the smile as he held out his hand. "If we're going to be working together, just call me Shotaro."

Ben took the hand. "Tennyson, Ben. Just call me Ben. So," he said after they finished shaking. "What exactly is a Dopant? And that….what did you call it again? Gaia Memory?"

Shotaro took off his hat to run a hand through his hair. "Gaia Memories are the source of a Dopant's power. They look like USB drives."

"Oh, I get it. Memory drives. But what does the Gaia part have to do with it? Wasn't she a goddess in Greek Mythology or something?"

"Titan actually," Shotaro politely corrected. "The embodiment of the Earth itself."

"Knew I should've brushed up on my mythology," Ben said with a snap of his fingers. "So what you're saying is—"

"Gaia Memories are the Earth's memories," Shotaro finished for him. "The one we're up against, the Magma Memory, represents the aspect of magma and everything related to it."

"So I noticed," Ben said as he looked over the bridge at the line of lava still bubbling in the road.

"Dopants are people who use Gaia Memories," Shotaro said, making Ben whirl around.

"Wait, that was a person?! A human?"

"Why do you think I assumed you were a Dopant?" Shotaro asked.

Ben's jaw dropped. "So you're saying there's these things running around that regular people can just use to turn into monsters?"

"Basically," Shotaro said grimly. "But how effective the memory works depends on how compatible you are with it. Memories work better with certain people than others."

"And just how many of these Gaia Memories are there?"

Shotaro took a few steps forward, looking out into the city. "I don't know but from what I know about them, it's possible there's a memory for every single word in existence."

Ben walked in front of Shotaro "How have I not heard about them? These memories, they're obviously dangerous. I mean, I have enemies back home who would literally do anything to get their hands on something like that. Can you imagine what would happen if someone made an army of Dopants?"

"I understand what you're saying," Shotaro said, appreciating how dire Ben was treating the situation. "But so far Gaia Memories have only been distributed in Futo."

That threw Ben off. "What, really? Only here? But why? Even if no one tried to make an army, these Gaia Memories sound perfect for arms dealers. I mean, I can imagine some alien arms dealers coming here just to get their hands on them."

Shotaro sighed. "Still can't believe aliens actually exist." He paused. "Now I feel bad for all the times I told Jinno I saw a UFO."

"Huh?"

"Long story," Shotaro said with a wave of his hand.

Ben nodded. "Okay but if the Gaia Memories are staying in the city, then the ones behind them must want them to. Would you happen to know who is making them?"

Shotaro shook his head sadly. "Unfortunately no. Whoever's behind them is good at covering their tracks."

"Right," Ben began pacing back and forth. "At the moment we should worry about that Magma Dopant. If Dopants are humans, then I'm guessing his real identity is Yousuke Togawa and he's attacking Windscale buildings for laying him off. Which means the important thing is figuring out where he's going to strike next."

Shotaro smiled, impressed. "Good job, that's exactly what we have to do. You really do have experience. Some of your adventures involve investigating?"

"Some," Ben said with a shrug. "I'm guessing we need to figure out how many Windscale buildings are left and which one's his next likely target?"

"Exactly," Shotaro nodded in approval. "You just might work with my hard-boiled style, Ben."

Ben chuckled. "You're really into this hard-boiled stuff, Shotaro. But how do we find out how many Windscale buildings are left?"

"That," Shotaro said confidently. "Is a job for my partner."

"Partner? That Philip guy?"

"Uh huh. Time to head back to the office."

/*/

As night fell upon Futo, the limousine that had been blocked by traffic finally passed through the gates to a grand estate. On the gate's plaque was written the kanji for Sonozaki. The woman from before was soon inside the manor, climbing up the stairway to the dining room as fast as possible. Her heels clacked against the stairs.

Inside, a man and woman were laughing as they sat down to eat. The man, an elderly man with short gray hair and round glasses who sat at the head of the table, was laughing. In his lap sat a blue tortoiseshell British shorthair cat. The woman, who was sitting to his right, laughed as well. Her hair was neatly tied into a bun and she wore a black dress. Their laughter was cut short as the woman from the limousine entered.

"If you were a member of my company," The woman who was sitting down said with a smirk. "I would've fired you for being tardy, Wakana."

Wakana clicked her teeth in annoyance as she made her way to the chair at the left of the table, further away from the other two. "I was in a traffic jam, it was really strange" She said, trying to act as casually as possible as she sat down. A waiting servant pushed her chair in and lifted the lid of her plate. "And it was even on the day of our dinner party."

"Buildings melt and people die," The man said, amused as he held his fork in front of his cat. "Such things happen in this city. Well, such is our line of work."

"Oh, were you right on the scene, Wakana?" The other woman said, strangely interested. "Did you see anyone out of the ordinary there?"

Wakana raised her brow and tilted her head at the other's curiosity. She had to keep a straight face as the woman raised a brow back and was sending her a condescending smirk. The typical signs of "I know something you don't know".

"Why the sudden interest in what happened, Saeko?" The man asked casually as he stroked his cat's back.

"I've learned something very interesting today, father," Saeko said, almost looking giddy. "But Wakana, did you happen to see an American with a green jacket at any time?'

Wakana's retort was cut short as she vaguely remembered at least someone with a green jacket. One of those three who were clownishly trying to sneak into the tunnel. "Maybe. Why?"

Saeko's smirk grew. "I heard that Ben 10 is in Futo."

"Oh?" The father looked up, very interested and even more amused. Even his cat curiously looked up.

Wakana tilted her head, mentally scratching it to remember where she had heard that name. Her eyes widened. "Wait…that American who they say turns into aliens?"

"The very same," Saeko said, leaning back in her seat smugly. "He was spotted by one of our distributors earlier today."

"Ah, Ben 10," the father said, scratching his cat behind the ears. "I hear he's actually quite popular amongst our buyers."

Saeko nodded her head towards her father. "He is. Often those who buy our Memories say things like "I can transform like that American, Tennyson?" or something similar."

"But why is he here?" Wakana asked.

"I believe it's quite obvious," The father started to smirk as well.

"Perhaps someone in the city is a fan of his and asked him to fight the Dopants," Saeko suggested.

"So, he really can turn into aliens?"

"We'll see what happens when he meets a Dopant face to face, which will no doubt be very soon," the father said, feeding his cat another piece of his dinner. "By the way, Saeko, who was it that informed you of Tennyson's presence? Would it happen to be the same one I hear has been doing a splendid job at selling our Memories?"

Saeko chuckled as she turned towards her father. "Actually father," she rose to her feet and pulled out a tanned USB in a casing resembling bones. In the middle was a cursive T drawn to resemble a pair of lips. She pressed a button on the drive.

TABOO!

The father put a calming hand on his cat, who had let out a growl at the voice coming from the flash drive.

Still smiling, Saeko jabbed the drive into the slot of a silver belt around her waist. The drive was absorbed into the belt as Saeko's body morphed into what was essentially a red rag doll with a lower half like a caterpillar. Her eyes were gone and her hair resembled stalks of grain where a red woman figurine was peeking through.

"I have found someone I wish to marry." Saeko said as she ran a hand around her mouth, stitches stretched from both corners of her mouth to the sides of her head.

Wakana rose from her chair, staring at her transformed sister in disbelief as their father let out a deep chuckle. Whoever managed to become Saeko's fiance must be someone impressive to say the least.

/*/

The sound of Shotaro's motorcycle shot through the night air as he brought it to a stop by the agency. Before going, he had bought Ben a motorcycle helmet. Once Shotaro put up the kickstand, Ben climbed off.

"One thing I don't get though," Ben said as he took his, fittingly, green helmet. "Being laid off can't be the only reason he's doing this. I mean, it's rough but that doesn't justify destroying all those buildings."

"Agreed," Shotaro said as he removed his own helmet. "Chances are that Windscale wronged him in some way and the lay off was the cover story. I hear the world of fashion can be a cutthroat world. Whatever Windscale did to him was bad enough that he purchased a Gaia Memory for revenge. Course it's also possible that he didn't meant for things to go this far."

"What do you mean?" Ben asked as he held his helmet in the crook of his arms as they made their way to the stairs of the second floor.

"Gaia Memories do more than grant powers," Shotaro said soberly. "They are addictive and using them over and over takes a toll on the user's mind."

Ben froze. "So they're not just weapons…they're drugs. Drugs that give you super powers."

Shotaro nodded, his head down low. "Right on the mark."

This realization brought a grim scenario to Ben's mind. If Gaia Memories ever made it to America, he could imagine how many people would clamor to get their hands on even one. Especially if they happened to be his fans.

Hey, kids! You want to transform like Ben Tennyson? Well now you can, with Gaia Memories! Just take one and you can become a hero too! Get your Gaia Memory today!

"Shotaro?"

"Yeah?"

"Have—have any kids been given Memories?"

"No, thank goodness," Shotaro said instantly, a dark expression on his face.

The rest of the walk up to the office was quiet, but it certainly didn't last long when Shotaro found the door open and a pile of boxes gathered right outside it.

"What is this?!" the detective exclaimed.

"Something tells me Akiko didn't go back to her hometown," Ben muttered as Shotaro shot into his office. Ben quickly followed after him, pausing when he noticed that the coat rack side of the wall had revealed a hidden door. One of the fedoras must have been put over the now visible door handle so nobody would notice. Shotaro ran through the door and Ben followed, revealing some kind of hangar room.

There was a spiral staircase that led up to a platform where a stepladder stood beside a whiteboard covered in kanji. Across the other side of the room was another whiteboard where someone was writing in a black marker and muttering to himself, an open book in his left hand. The aforementioned Philip no doubt. With his back turned, all Ben could make out was that he had short black hair that looked brushed to the left. He wore a long, blue hoodie without sleeves, revealing the shirt underneath was a long, white shirt with green, horizontal stripes. Akiko was standing beside him, her expression a cross between sheepish and uncomfortable.

"Middle schooler!" Shotaro snapped in frustration, causing Akiko to flinch. "Why are you here?!"

"Hey, Shotaro," the young man said without even turning his head, though he did occasionally glance at his book. "Our guest is great, she gave me something new and exciting. A whole new look up sensation!"

Akiko fiddled with the tips of her hair as Shotaro glared daggers at her. "Look up sensation?" Ben said to himself curiously.

"I bet you didn't know about–" Philip finally turned around and Ben noticed that the right side of his head had various clips in it. Philip then slammed his palm against the whiteboard. "The delicacy known as takoyaki?!"

Shotaro gave him a quizzical glance that slowly changed to horror as he looked at the whiteboards over. Also curious, Ben squinted his eyes at the whiteboard. If he remembered his lessons correctly, the kanji were various notes about takoyaki. He couldn't remember the details but Ben knew it was a type of snack where octopus was the ingredient he remembered the most.

"Takoyaki, kobe, broth," Philip rambled, eyes glued to his book. "My research has pulled up 3,543,280 related results. "

"That many results from one snack?" Ben's jaw dropped.

"Exactly," Philip said with a smile before diving back into his book. "Such an interesting way of eating."

"Don't encourage him," Shotaro grunted before marching over to Akiko, who scurried up another stepladder. "Unlike you, middle-schooler. You just had to say something didn't you? Now you got him sidetracked!"

"How was I supposed to know?" Akiko defended herself. "What's up with him anyway?"

"Maybe he just—really likes learning?" Ben suggested with a shrug.

Shotaro scoffed at that. "Learning, nothing. He loves researching, especially new topics he's never heard of. But now that he's off track, I can't get him to focus on the Dopant case."

"You really can't get him to focus on the case again?"

"Oh trust me. Once he gets going, he will not stop until he's learned everything he can from his research."

"Well, in the meantime, maybe we can try to go over what we do know," Ben offered. "To make it easier for us to track the Dopant down."

Akiko hopped off the ladder and stomped over to Shotaro. "Dopant, Dopant, Dopant! What is a Dopant?!"

"The monster that attacked us earlier," Ben told her. "Or rather, a human who turned into a monster."

Akiko learned, mouth agape. "Eh?"

Shotaro went over to a desk near the whiteboard where a computer was activated. Fiddling with the keyboard, he brought up a picture of a red flash drive with a bone-like casing. In the middle was a stylized I meant to resemble a bone and knee cap. Ben also noticed that in the top left corner, written in red was the English word INJURY.

"Gaia Memory," Shotaro said, turning around to face Akiko."People who use them turn into superhuman monsters: Dopants."

"Injury?" Ben read aloud. "So a Dopant like that would have power over injuries?"

"That's right."

"How does that work?"

"You don't want to know."

Akiko scoffed. "That's just ridiculous."

"Uh, don't you remember what happened earlier?" Ben asked, rubbing his head. "I think I still have the bumps to prove it."

Akiko sheepishly looked at her feet, realizing she couldn't dispute what she had been told.

"Akashiyaki?" Philip wondered aloud, pacing back and forth. "Kobe takoyaki? Tamago yaki?"

"Unfortunately," Shotar said as he ran a hand through his hair. "There's not much we can do at the moment. Not with Philip being like this."

"We really have to wait it out?" Ben asked.

"Only thing we can do," Shotaro said, leaning a circular structure connected to a lower platform on the hangar floor.

"Maybe we can go out on patrol or something?" Ben offered.

"Probably wouldn't do any good. Togawa might lay low or now since the cops will be out looking for it. Besides," Shotaro added with a whisper. "If they see one your—you know what, the cops might mistake you for a Dopant too before you can explain things. Not to mention iit might drive Togawa into hiding."

"Fair enough," Ben said reluctantly.

"You mean his a-," Shotaro hastily covered Akiko's mouth. Philip looked over his shoulder and Shotaro responded with a big, bright smile. Nonplussed, Philip resumed his reading.

"Ben already said he'd explain everything after this case," Shotaro whispered to the glaring Akiko. "If Philip learns about Ben's—abilities beforehand, we'll never find the Dopant." He slowly let go of her mouth. Akiko responded by pulling out her green slipper

BONK!

Shotaro winced and glared at Akiko, who simply glared back. Ben shook his head before looking back at Philip. "Hopefully this won't take too long."

Shotaro laughed sarcastically under his breath.

/*/

The sound of Philip's book slamming shut boomed throughout the hangar. "I have read everything about takoyaki!"

Ben, who had been lying down on the platform closest to the door, and near the spot Philip was currently standing, sat up with a shot. He blushed as he felt a bit of drool on the corner of his mouth but Philip didn't seem to notice. On the other side of the room, Akiko had draped a blanket around herself with a pillow under her chin. Shotaro had apparently fallen asleep with his back propped up on the ladder.

After a yawn, Shotaro rose off the ladder. "Now, please hurry back to the Gaia Library."

Philip nodded with a grin. "Right."

Ben rose to his own feet, wincing as his back felt stiff from where he slept. "Gai-" He yawned, still shaking the sleep off. "Gaia Library?"

Instead of answering him directly Philip took a few steps forward and closed his eyes, bringing his hands together before spreading his arms apart. A hum filled the air and his body seemed to glow.

"...Okay, I don't know what I was expecting but this is definitely not it," Ben said to himself.

"Beginning lookup," Philip said, his eyes still closed. "The Memory is: Magma."

Ben tilted his head as Akiko started to ask Shotaro what was going on, only for the detective to bring a finger to his lips with a sharp "Shush!" Akiko but did not press further. Shotaro then walked towards Philip.

"I need to know where he'll attack next. First keyword: Togawa Yousuke."

After a minute, Philip spoke up. "That really narrowed the search down."

"Probably because it's a person," Shotaro rationed. "Second keyword: Windscale. That's the name of the company who laid him off." Then he pulled out the pictures Jinno had handed him, flipping through them until he reached one with a tag on some clothing in the picture. "Next, look at the numbers: WS-09K-097T."

Another moment passed. Philip's eyes opened. "It was a good idea using the product number on the tag." Taking the picture from Shotaro, Philip held it up, looking it over before opening his book. "This product is only sold at select locations. The only one that hasn't been attacked yet is the Windscale, Kazetani branch."

Shotaro nodded, heading towards the door. "Let's go, Ben, Philip."

"On it!" Ben called, going after the detective, deciding to wait till after the case to ask about what Philip had just done.

/*/

The two, helmets in hand, went toward Shotaro's bike. It wasn't until Ben put his helmet on that he realized something. "Hey, I thought Philip was coming with us."

"Don't worry, he is," Shotaro said as he started up the engine. "The two of us are one detective. Hop on."

"Oooookaaaay," was all Ben could say as he climbed onto the seat.

"Sho-chan?"

The two turned their heads to see Marina standing to their left, looking at Shotaro in confusion and hope. Shotaro simply gave her a two-finger salute before shooting onto the street, Ben just barely managing to hold onto him in time.

/*/

When Shotaro's bike came to a stop, Ben immediately hopped off. The Windscale building seemed to be connected to other stores. Part of a mall most likely. Aside from seeing people in the store itself through the windows, there were people walking around or sitting at outdoor tables. Shotaro stood beside him, also scanning the area. His face became set and he tapped Ben's shoulder. When Ben looked at him, Shotaro pointed forward. Following his direction, Ben spotted a man glaring at the Windscale building. He matched the photo Marina had provided perfectly. Shotaro made his way towards the man with Ben right behind.

"Togawa Yousuke, right?" Shotaro said. The man turned his head to Shotaro.

"Are you one of the employees here?" he asked. Shotaro was surprised that was the first thing he was asked. The man rolled up his left sleeve to reveal a tattoo on his forearm that looked exactly like USB port. He then raised his right hand, revealing that he was holding a red USB. "Then—"

MAGMA!

"Burn!" Togawa yelled as he jabbed the Memory into the port. Fire began rising from the port and spread across his entire body, even his eyes looked like they were on fire. Ben and Shotaro retreated back from the flames as they engulfed Togaway's body. Screams filled the air as pedestrians became aware of the fire, running as fast as they could, crashing into each other or knocking over the tables and various stands gathered around.

Another great burst of flames and the Magma Dopant stood in Togawa's place. Now that Ben had a better look at him, the Dopant's face looked like a skull with no lower jaw where instead flames poured. His skin looked like volcanic rock and Ben could just make out cracks along his body. If he didn't know that the Dopant was a transformed human, he might have thought he was some cousin of Heatblast, albeit more monster looking.

The Dopant let out a roar, emitting more flames from his body. Shotaro yelped as the flames slightly singed the edge of his hat. Quickly stepped back further, he hastily put out the flames. Once he was certain they were all put out, he put his stttill slightly smoking hat back on his head and faced the Dopant coolly.

"I'll stop you," he said then he smiled. "No, we'll stop you."

He pulled out a red and silver object. The red part in the middle look like two slots with transparent middles. Before Ben could ask, Shotaro attached it above his belt buckle. Another, thicker belt emerged from the left side and wrapped its way around his waist and connected to the right of the buckle. Another, black slot emerged at Shotaro's right hip. Reaching into the left side of his vest, Shotaro produced a purple USB, closer to a regular drive than the one Togawa used. In the middle was a light purple J that seemed to be made of flames. Shotaro pressed a button on the drive.

JOKER!

Both Ben and the Dopant stared at the drive in Shotaro's hand. "Shotaro is that what I think it is?"

"This," Shotaro said, never taking his eyes off the Dopant. "Is a different kind of Memory. Phillip!"

"Philip?" Ben looked around. "Where?"

Shotaro then swung his right arm across himself. "Henshin!"

Ben was about to ask what was going on when a flash of green light came from the slot on Shotaro's right. A green USB now occupied it. Without even looking, Shotaro pushed down on the drive. The image of a stylized C made out of a gust of wind appeared in midair as the belt began humming and whirling. Turning the drive in his hand over, Shotaro pushed it into the other slot, causing an image of the fiery J to appear. Crossing his arms, Shotaro pushed the two slots in opposite angles, making the buckle vaguely resemble a W.

CYCLONE! JOKER!

The wind suddenly picked up as flashes of green and purple light gathered around Shotaro, covering his body. There was another flash and the sight caused Ben's jaw to drop. Shotaro was now donned in armor that was green on the right side and black on the left. A gold line ran from his right shoulder and upper chest and a purple line ran from his left shoulder and left upper chest. Gray lines ran down the middle of his body, his eyes were red and circular, and he wore a white scarf around his neck.

Ben licked his lips multiple times before he finally found his voice. "Shotaro, you're—you're one of the Kamen Riders?!"

"That's right!" The armored figure said and Ben's eyes bugged out when he heard what was clearly Philip's voice alongside Shotaro's. "The two in one detective: Kamen Rider Double!"

The wind got even stronger, weakening the flames of the Magma Dopant, who struggled to keep his feet planted.

"Now," Kamen Rider Double shifted his stance and pointed at the Magma Dopant with his left hand like a gun. "Count up your sins!"

"Sweet catchphrase," Ben couldn't help saying as Double charged at Togawa, unleashing a flurry of kicks one after another on the Magma Dopant. Togawa could only grunt in pain as blow after blow struck him. As Ben watched Double move, he remembered a conversation he had shortly before going to Japan.

"Uh…Common Riders?"

Ben was in the old RV the Rustbucket with Kevin, Gwen, and his grandpa Max.

Grandpa Max chuckled. "No, Kamen. It's the Japanese word for Mask."

"The Masked Riders?" Kevin said. "Sounds like the name of a cowboy show."

"To be fair," Ben spoke up. "Kamen Riders does have a nice ring to it."

"From what I've looked up," Gwen said, tucking a strand of her auburn hair behind her ear. "The Kamen Riders are symbols of Hope and Justice in Japan. The people really look up to them."

Kevin smirked. "So Ben's either a threat or menace but those guys are hope and justice huh?"

"The Kamen Riders have been reportedly active since the 70s," Grandpa Max spoke up. "Which means they've had decades of proving themselves to the public."

"So maybe after a decade or two, people will think the same about him," Kevin said. "Hey who knows? Maybe working with these Kamen Rider guys can help you build up some goodwill in Japan at least."

Ben made a face at his best friend before smiling at his grandpa and cousin. "All joking aside, it honestly does sound pretty cool to team up with heroes from another country. I'm looking forward to meeting these Kamen Riders."

Double jumped, striking the side of Togawa's face with his right foot and sending the Dopant flying through the air and sprawling to the ground. Just as Ben started to feel he wasn't needed, Togawa rose to his feet with a snarl. The fire in his body burned even brighter before fireballs erupted from his back like a volcano. Double dodged to and fro as the fireballs struck the ground, driving the Kamen Rider back.

"Sure is hot," Double grunted, though only Shotaro's voice was heard.

"Allow me, Shotaro," Ben activated the Ultimatrix, causing the interface to pop up like a dial and display a holographic image. He began turning the dial, displaying a different image with each turn. "I think a little Water Hazard oughta cool him off."

Snarling, Togawa turned towards, launching fireballs at the American hero

"Ben, look out!" Double cried out.

His soccer reflexes kicking, Ben dove to the side, rolling away from the fire balls. He grinned at the Magma Dopant and raised his right hand. "It's Hero Time!"

He slammed the dial down, creating a bright flash of green light that made both Double and the Dopant turn their heads away.

"W-what was that, Shotaro?" Philip's voice asked, the right eye flashing as Philip spoke.

"I'll tell you after this is over," Shotaro's voice explained as the light faded, the left eye flashing now.

Standing in Ben's place was a small, white humanoid creature wearing headphones that connected to what appeared to be an MP3 player on his back sporting a 10 symbol. He had what appeared to be cassette tapes on his legs and circular indents on his hands. He had bright green eyes and a dark green mouth. The creature looked at himself and his eyes widened.

"Echo Echo?!" He shouted in a high pitched, robotic voice. "Oh man, I must've accidentally switched aliens when I dodged!"

"Eh?" Philip said, making Double tilt his head. "Did he just say aliens?"

"Focus, Philip!" Shotaro snapped as the Magma Dopant growled, advancing toward Echo Echo. "Oi, Ben! I think you've put yourself in a pinch."

Echo Echo smirked at him. "Hey, it may not be the alien I wanted but haven't you heard size doesn't matter. Also, strength in numbers!"

Both Double and Togawa gawked as one Echo Echo became six, running around the latter and forming a circle.

"He duplicated himself, Shotaro," Philip said in awe as the Magma Dopant glared at each of the surrounding aliens, each one grinning confidently at him.

"Echo Chamber!" They yelled as one before blasting supersonic waves at their enemy. Togawa grabbed his head, yelling in pain from being bombarded by sound in every direction.'

"The power to copy himself and a sonic scream," Shotaro noted. "Now that is useful."

"So this is an alien," Philip said, his voice rising in excitement. "An extraterrestrial, a creature from another planet. He also said aliens, as in more than one. I must know more!"

"After the Dopant is dealt with!" Shotaro said quickly. "Now, Ben's got him pinned down so let's wrap this up with a Memory Break." Pulling the Joker Memory from his belt, he placed it into the right slot on his hip.

JOKER! MAXIMUM DRIVE!

The wind gathered around Double once again, forming a cyclone that lifted the Kamen Rider up into the air, his scarf flapping in the wind. The Echo Echos all ceased their attack, looking up at their ally curiously.

"We'll take it from here, Ben," Double launched himself at Togawa, feet first. "Joker Extreme!"

The Echo Echos all dove out of the way as Double seemed to split right down the middle. The Joker half struck the Magma Dopant first, immediately followed by the Cyclone half. Surges of green and purple energy flashed as the two halves struck Togawa, sending him flying once again. Echo Echo and his clones braced themselves as the Dopant weakly pushed himself up but no sooner had gotten back on his feet, his body exploded in another burst of flames. As the fire quickly died down, Togawa was revealed back in his human form, falling backwards. The Memory had been ejected from his body, falling to pieces as it struck the ground near his feet.

"So that's that?" Echo Echo asked his clones began receding into him.

"That's that," Double answered softly. "I'll leave the rest to the police. Still, what am I supposed to tell Marina?"

"What can you tell her?" Echo Echo inquired gently. "Chances are she's gonna find out sooner or later."

"Yeah, I know," Double replied, lowering his head. Before anymore could be said, the ground started shaking.

"Uh, do you get earthquakes in Futo?" the alien hero asked nervously.

Before Double could respond, something burst from the ground behind Togawa with a vicious growl. Its features were somewhat obscured by the debris it was kicking up but it had a massive head and a large jaw with rows of teeth. In fact it looked strangely like—

"A T-Rex?!" Echo Echo exclaimed. "Underground!"

The T-Rex monster began using its jaw to kick up the concrete in its way as it seemed to be making a beeline for Togawa! The former Memory user was too scared and possibly too weak to escape. Echo Echo jumped between him and the dinosaur, unleashing a sonic scream that caused the T-Rex to howl and thrash in pain. Double ran over to help Togawa up. The T-Rex titled itself back before slamming its head on the ground, the force knocking Echo Echo into the air. A bony tail swung around, striking both the alien and Double, sending them flying to the side. Double crashed into a fence while Echo Echo flew right over it, rolling downhill. Double look in time to see the T-Rex grab Togawa with its teeth.

"Stop!" Double said as he pushed himself to his feet. But Togawa's screams were cut short as the poor man was dragged underground.

"No!"

Double turned around to see Echo Echo leaping over the fence. His hand struck the symbol on his chest and there was another burst of light. Once the light faded, the tiny alien was replaced with a ten foot tall creature that resembled a yellow, robotic bipedal armadillo with a head like a Greek warrior's helmet and jackhammer-like features on his elbows, wrists, and hands.

"Say hello to Armodrillo!"

"Shotaro! He transformed again!" Philip said giddly.

"I can see that, Philip," Shotaro replied. "Just how many of those things can he turn into?"

The T-rex's head emerged from underground, shooting forward to take a chomp out of the new assailant. The new alien swung a piledriver fist and uppercutted the creature under its jaw. The T-Rex roared in pain as its head shot back. Its tail lashed out to hit Armodrillo, who quickly caught it. However, the T-Rex recovered from the blow and chomped onto Armodrillo, trying to bite into it. It let out several growls as its teeth failed to penetrate the alien's armor.

"Aww, too hard for you?" Armodrillo taunted as he brought his fist back. "How's this for a jawbreaker?"

He punched the side of the t-rex's mouth, creating a shockwave that forced the dinosaur to release him as it was knocked back. As it did, he noticed the dinosaur's body looked like a combination of rubble and debris merged together to crudely form the body of a tyrannosaurus. Was this some sort of t-rex golem the entire time? Snarling, the T-Rex shifted its body and prepared to dive back under ground.

"Oh no you don't!" Armodrillo yelled, lunging at the makeshift dinosaur. The T-Rex turned its head and let out a powerful roar that actually launched the hero backwards. "Hey! No fair copying me!"

The moment Armodrillo was airborne, the T-Rex dove back underground. Double ran to the hole the monster had left but was forced to roll out of the way from the creature's lashing tail. A crash nearby showed Armodrillo lying on the ground, leaving a small crater from the impact. Pushing himself up with a groan, he just saw the T-Rex disappear. "Hey, you're not getting away, buddy!"

He ran to the hole and prepared to dive, only to find himself pelted with a bombardment of debris and rubble. Armodrillo grunted, knocking as much debris as he could as dust got into his eyes and mouth. The T-Rex turned one more time to let out another powerful roar, launching Armodrillo into the air once again.

"I'm getting really tired of that!" The alien yelled as the T-Rex disappeared underground. Double ran over to where Armodrillo landed, covered by the debris and rubble that had also been knocked up by the dinosaur's roar.

"Ben, are you alright?" Double asked as the alien hero pushed the debris off himself.

"I'm fine," Armodrillo said as he brushed himself off. "The only thing that hurts is my pride. I've got to go after that thing!"

Double shook his head "Don't bother. That thing will be long gone and probably in its human form by now."

"Are you sure? Armodrillo moves through dirt like air. I should be able to catch up to it."

"Yeah but how well do you know your way around the city?" Double countered. "Chances are that Dopant will lead you on a chase throughout Futo, destroying who knows what."

Armodrillo flinched as he remembered something else his grandpa had said before they left.

"Ben, I understand things happen in the heat of the moment but some of your battles can cause some serious collateral damage. The last thing we need is for you to be blamed for an international incident due to foreign property damage."

"In short, Ben," Gwen had added. "Make sure to fight smarter, not harder."

"And make sure that if things do hit the fan, you get yourself a really good lawyer. Like the best lawyer in the entire world." Kevin couldn't help adding with a smirk.

"I should've used Big Chill instead of Armodrillo," the alien hero said, wanting to smack himself in the face. "I was really cutting it close just now."

"Big Chill?" Philip inquired. "Another alien. I'm assuming he has powers related to ice from his name."

"And ghost powers," Armodrillo added.

"Eh? Ghosts now?"

"Not yet," Shotaro snapped. "I said after this case is over and it looks like it's far from over." Double looked over at the hole left behind by the T-rex.

"Gonna just assume that was another Dopant," Armodrillo was covered in green light before turning back into Ben. "Was it here to get Togawa away from us?"

"From the way Togawa was reacting, I don't think that Dopant came to save him," Double said grimly.

Ben put his hands in his pockets as he looked over the whole as well. A cold wind below across the heroes as they tried to figure out what would happen now.

End of Part 1

Originally I had tried to figure out how to do a crossover between Ben 10 and Kuuga.

The idea was that the crossover replaced Alien Force. Ben is part of a Foreign Exchange Program to Japan but doesn't get to enjoy the sights as the murderous race called Gurongi are freed from their sealment and begin killing humans as part of a twisted game.

Not knowing what exactly is going on, Ben still dons the Omnitrix once again to stop these monsters. The Gurongi, intrigued by a human who turns into monsters, decide to make their game more interesting against Ben. But the wielder of the Omnitrix finds an ally against the Gurongi; the man who fights for people's smiles: Kamen Rider Kuuga!

However, rewatching the Kuuga episodes, I saw that it would be tricky to say the least, even for a one-shot special so I decided to pick a different Kamen Rider series instead.

I had briefly considered Agito but I wasn't sure if Ben really fit into that series. I could see Fourze working since it is space themed but that was predictable, especially since people have done Fourze and Ben 10 crossovers before.

Then I settled on Kamen Rider W/Double. I'm a huge fan of the series. I love the dynamic between Shotaro and Philip, I love detective stories, I honestly enjoy the Gaia Memory gimmick plus the half and half motif of Double. Not to mention I love the catchphrase "Count up your sins!"

If anyone would love to watch Kamen Rider episodes, I recommend the website . It has episodes from Kamen Rider Skyrider all the way to the current series Kamen Rider Geats. It also contains episodes for Super Sentai (From Liveman to Donbrothers).

Well guys, I think that's all I've got for this part. See you in the conclusion with Part 2!