Disclaimer: I do not own Smallville, Arrow, or The Flash.

For a while, I've been wanting to do my own spin on the Arrow 5x23 arc involving Smallville characters and, after recently rewatching some episodes of Arrow Season 5, I finally got around to it.

Before we get started, here is a summary of events that are different from canon on the Arrowverse side. The events of my fic "Alternate Events: When Heroes and Universes Collide" did happen here. For those who haven't read it, it's basically an AU where the Tachyon enhancer in The Flash 2x18 sent Barry to the Smallville Earth (which I call Earth-21) instead of Supergirl's. However, despite very similar happenings, this fic isn't actually canon to the "Alternate Events" series.

The difference between "AE" and this fic is that, here, Flashpoint caused additional changes to the timeline: Laurel was visiting her mother in Central City at the time of the particle accelerator explosion and developed a Canary Cry as a result. Also, she was never killed by Damien Darhk, although Oliver still killed Darhk in the Season 4 finale, and he and Laurel rekindled their relationship at the beginning of Season 5. Earth-2 Laurel/Black Siren still showed up, but as in canon, she joined Prometheus' team. Roy returned to the Star City sometime after the "Invasion" arc, was pardoned by the president, and is once more part of Team Arrow. As for Dinah Drake, she doesn't exist for the sake of this story.

As for The Flash, Barry ended up with Caitlin instead of Iris, who eventually moved to Keystone City, and it was Caitlin whom Savitar intended to kill. For this story, Caitlin never developed ice powers and didn't get hurt in the Abra Kadabra episode.

Another difference from "Alternate Events" is that, while Conner Kent still helped out during the Dominator invasion, he simply returned to Earth-21 with Clark and Ollie instead staying behind to join the Legends, as Courtney Whitmore (who I have as Conner's love interest in that series) was never killed here.

Chapter 1

Earth-21

(Metropolis, Clark and Lois' apartment)

Clark Kent was sitting on the couch reading a newspaper, while his wife, Lois Lane, was sitting next to him typing an article for the Daily Planet on her laptop.

Suddenly, a crackling noise got their attention as they turned to see some kind of portal opening in the middle of the living room.

"What the hell?" Lois exclaimed, while Clark immediately recognized it as one of those breaches that Cisco Ramon or his inter-dimensional extrapolator device made to travel between universes.

They watched as a dark-skinned young man clad in some kind of yellow and red suit, a middle-aged black man, and an attractive Caucasian woman with reddish-brown hair stepped out of the breach before it closed.

Clark regarded the three newcomers in surprise, only recognizing two of them. "Wally? Dr. Snow?"

"You can call me Caitlin," Caitlin told him.

Clark turned to the middle-aged man. "And you are?"

"Joe West, Wally's father," the man introduced himself.

"Nice to meet you, Mr. West," Clark said as he and Joe shook hands. He turned to his wife. "Lois, these are friends from that other Earth that Oliver, Conner, and I visited months ago when we helped them stop the Dominators."

"Hi, I'm Lois Lane, Clark's wife," Lois said with a smile as she waved at the visitors and shook their hands.

"We apologize for showing up in your apartment like this, but we need your help," Caitlin said.

Clark got up, an alarmed look on his face. "What's going on?"

"It's Savitar," Wally replied.

"Who?" Clark asked.

"Savitar is what we call the enemy speedster we've been dealing with for the past year," Caitlin explained. "He wants to kill me to ensure his own existence."

"That's why we came here to your Earth," Joe said. "We need to keep Caitlin safe."

"Will you help us please?" Wally asked.

"Sure, no problem at all," Clark nodded. "In the meantime, while Caitlin is here, I'll go to your Earth and help take down this Savitar."

"You can't or Barry will figure out which Earth we're on," Wally said.

"Barry can't know where I am," Caitlin added. "Because if Barry finds out, then Savitar will find out too since Savitar is more or less a future version of him."

"What?" Clark asked in disbelief. "Are you saying that Barry lost his way and became Savitar in the future? And how does killing you ensures his existence?"

"It's quite complicated to explain, but Savitar is not exactly the future version of our Barry," Caitlin explained. "He's a time remnant of Barry that Barry, in a future where I was killed, created in order to stop Savitar."

"What's a time remnant?" Clark asked, confused.

"Speedsters have the ability to run back in time and create what is essentially another version of themselves, which is called a time remnant," Caitlin explained.

"I don't think Bart ever displayed such an ability," Clark said. "Either he doesn't have it or he simply doesn't know how to use it. Anyway, let's get you to Watchtower. You'll be safe there. If Savitar does show up here, my team and I will be ready to take him down."

"Thank you," Caitlin said, with a smile.

Clark rapidly sped around like a tornado and was clad in his Superman suit a moment later.

"I'll see you later, honey," Clark said to Lois, before giving her a quick kiss on the lips.

"Go take care of your business, Smallville," Lois said, with a smile.

(Watchtower)

Caitlin, Joe, and Wally followed Clark into the main room of Watchtower. Oliver Queen and John Jones were each working at a computer. Bart Allen was playing cards with Chloe Sullivan on one of the couches, while Tess Mercer, who was currently in her human form, was sitting close to them. John Stewart and Dinah Lance were in one part of the base sparring with escrima sticks.

"Boy Scout, what's going on?" Ollie asked, as he and John Jones were the first to notice the newcomers.

"Oliver, you remember these people from the other Earth, right?" Clark asked, as he and the three Earth-1 visitors walked up to Ollie.

"You're Dr. Snow, right?" Ollie asked Caitlin.

"Yes, Caitlin Snow," she nodded.

Wally removed his cowl. "I'm Wally West." He gestured to Joe. "And this my father Detective Joe West."

"You're a detective too?" John Jones asked.

"That's right," Joe nodded. "I assume you are as well?"

"Correct," John Jones nodded. "Detective John Jones."

He held out his hand and Joe shook it.

Chloe, Bart, Tess, John Stewart, and Dinah all came over, and Clark introduced Caitlin, Wally, and Joe to them. The three visitors immediately realized that Bart was Barry's counterpart, while Bart was shocked upon meeting Wally, as the local Wallace 'Wally' West was a ginger-haired Caucasian police officer who worked at the Central City Police Department and didn't possess any powers.

Once the introductions were done, Clark, Caitlin, Wally, and Joe went on to explain the Savitar situation to the others and why he wanted to kill Caitlin. Ollie, Chloe, and Bart were shocked upon learning who Savitar actually was.

"So my namesake went evil in the future and is trying to kill his own girlfriend? Geez, that's insane," Bart said, shocked that someone as kind and virtuous as the Barry Allen he'd met over a year ago had fallen so far.

"Well, Savitar isn't exactly Barry," Caitlin pointed out. "He's a time remnant, a duplicate, from a future in which Savitar successfully killed me. If Savitar doesn't kill me, he'll have no reason to exist."

"So all we have to do is make sure that doesn't happen," Ollie said. "In that case, you three are welcome to make yourselves at home in our Watchtower."

Caitlin, Joe, and Wally were sitting on the couch with Bart, Chloe, Tess, and Dinah as they were conversing and eating a box of donuts, which Clark had brought for them. Clark, Ollie, John Jones, and John Stewart were sitting at the computers working.

Suddenly, a portal opened in the middle of Watchtower, immediately getting everyone's attention, and a large metallic figure made out of a suit of armor with its eyes and the inside of its body glowing with bright blue lights sped out of it, grabbing Caitlin and holding her up.

"I am Savitar, the God of Speed, and I will ensure that destiny gets fulfilled!" Savitar declared.

However, before he could react, a red blur sped past and Savitar suddenly found his hands empty.

"What the..." Savitar trailed off, unable to believe that anyone was possibly fast enough to catch him off-guard like that.

He turned to see Bart standing in a corner with Caitlin in his arms.

"How?!" Savitar wondered, eyes wide in shock. "I'm the fastest man alive! No other speedster can match the power of the God of Speed!"

"If you're really the 'God of Speed", I dare you to catch me," Bart taunted with a smirk.

With that, Bart sped Caitlin over to Clark before speeding out of the Watchtower. Roaring angrily, Savitar also sped out of Watchtower, pursuing Bart.

As the two ran through the streets of Metropolis, Savitar found that he was unable to catch up to Bart despite moving at his maximum speed. Bart turned around with a smirk and stopped running, giving Savitar a sarcastic wave as the metallic speedster ran towards him.

Savitar reached his arm out and was mere inches from grabbing Bart when the red-clad speedster suddenly took off again, running down an intersecting street. The chase continued for about ten more seconds before Bart turned around again and this time started running backwards as he gave Savitar a sarcastic salute.

"NO! THAT'S IMPOSSIBLE! NO ONE IS FASTER THAN ME!" Savitar roared, realizing that Bart was now merely toying with him. "I'M GONNA KILL YOU!"

A beam of heat vision shot down seemingly out of nowhere and struck the back of his leg, causing the self-proclaimed 'God of Speed' to fall on the ground as Superman and Martian Manhunter hovered over him. Savitar tried to get back up, only to hold his head and groan in pain as Martian Manhunter attacked him with a mental blast.

Superman then slammed his hands together, creating a powerful shockwave that shattered Savitar's suit into a million pieces as the insane future iteration of Barry Allen fell down, still clutching his head in pain. He looked around to find himself surrounded by Bart, Superman, Martian Manhunter, Green Lantern, and Tess in her Red Tornado form.

"Do it!" Savitar yelled like the madman he was. "Kill me!"

"You're a complete disgrace to the real Barry Allen by looking exactly like him," Clark said, disgust in his voice.

"We do not kill our enemies unless it's absolutely necessary, but we will see to it that you'll get nowhere near Ms. Snow tonight," John Jones said.

With that, Clark punched Savitar in the face with just enough force to render him unconscious.

"God of Speed, huh? More like the God of slowpokes," Bart quipped.

"From my understanding of time travel, as long as he doesn't kill Caitlin, he'll get erased from existence at roughly midnight," Tess said.

"Until then, we'll need to keep him locked in a secure prison," John Stewart said.

"I have exactly the kind of prison to keep him in," John Jones said. "Would you mind accompanying me to Mars?"

"Did you have to ask?" John Stewart said, before using his ring to encase the unconscious Savitar in a green bubble.

He and Martian Manhunter flew off into the sky with Savitar within the former's bubble construct as Clark, Bart, and Tess watched them.

"Looks like our job is done, amigo," Bart said.

"It is," Clark nodded. "Time to let Caitlin, Joe, and Wally know that Savitar is no longer an issue."

Earth-1

(Central City)

Once they were certain that Savitar had indeed been erased from existence, Clark, Ollie, and Chloe (who had decided to tag along due to her curiosity to visit another Earth) accompanied Caitlin, Joe, and Wally to Earth-1 as they all stepped out of the breath that opened in the cortex of S.T.A.R. Labs.

"Cait!" Barry called out, a wave of relief coming over him as he and Caitlin embraced and kissed passionately. "Oh, thank God." He held his girlfriend tightly, never wanting to let go.

As he then noticed the others, Barry let go of Caitlin and waved at them. "Hey, guys." He hugged Joe, Wally, Clark, Ollie, and Chloe one by one, while Cisco and H.R. congratulated Caitlin over surviving.

"We went to their Earth," Joe said to Barry, gesturing to the Earth-21 visitors.

"It's good to see the real heroic version of you again," Clark said to Barry.

"Is Savitar..." Barry started.

"He's been defeated," Clark assured him, much to Barry's relief. "We locked him up on Mars where John Jones and Green Lantern kept an eye on him until he was erased from existence."

Barry widened his eyes in amazement. "You guys took Savitar to Mars?"

"Yep," Ollie answered. "John Jones has a prison there specifically for those who are just too powerful to be locked away anywhere on Earth."

"It might've been a bit of harsh move, but we were willing to do whatever it took to make sure Savitar's chances of killing Caitlin remained at zero," Clark said.

"You should've seen them, Barry," Wally said. "Superman, that Bart guy, and the others took down Savitar like he was nothing."

"Really?" Barry asked.

"Well, Savitar was no God of any kind, that's for sure," Clark said.

"Thank you so much," Barry said. "I will always appreciate what you've done."

"You would've done the same if we needed help," Clark said.

"Do you or any of your merry band need help with any more baddies while we're here?" Ollie asked.

"Actually, there is one more thing," Barry said. "Oliver's family and friends have been kidnapped by an enemy of his named Adrian Chase. He just reached out to me to help him, but there are quite a few metas who just escaped and are teaming up and I can't help Oliver before dealing with them."

"So you want us to go," Clark realized.

"Oliver and I would really appreciate it," Barry said. "I will join you guys once my business here is done."

"Well, it looks like it's time for us to head to an alternate version of my home city," Ollie said.

"Let's just hope that Star City is on the same spot as our Earth," Chloe said.

"Wait, Chloe, are you sure you want to get involved in this? Oliver and I have this handled," Clark said.

"Look, Clark, just because I don't have any superpowers or wear a costume like the rest of you doesn't mean I'm useless when it comes to field work," Chloe pointed out. "Or did you forget that I'm almost as competent as my husband at combat skills?"

"Before we do anything, we're gonna have to make a really quick stop back to our Earth and fetch our gear," Ollie said.

"All right, but please make it quick," Barry said.

"We will," Clark promised, before he opened a breach with his extrapolator and he, Ollie, and Chloe leapt into it.

(Star City)

Oliver Queen, Malcolm Merlyn, and Nyssa al Ghul were in the Arrow bunker when the opening of a breach suddenly got their attention. A moment later, Clark, Ollie, and Chloe stepped out of the breach before it closed. Ollie was now wearing his Green Arrow suit, while Chloe was dressed in a black combat suit.

"Oh, it's you guys," Oliver said with relief upon recognizing Superman and his Earth-21 counterpart.

"We heard you need help taking down a man who kidnapped your loved ones," Clark said.

"That's right," Oliver nodded.

"Great to see you again, my doppelganger, " Ollie said, walking up to Oliver before the two shook hands. "Although I wish it was under better circumstances."

"For those of us who don't know them, who are these lovely new companions of yours, Oliver?" Malcolm asked.

"This is Superman," Oliver replied, pointing at Clark before turning to Ollie. "And believe it or not, this is Oliver Queen but from another Earth."

"What?" Malcolm and Nyssa asked simultaneously as they looked at Oliver in disbelief.

"Would you mind saving your sense of humor for after we've rescued my daughter and the rest of your allies?" Malcolm said in exasperation.

"It's not a joke, Malcolm," Oliver stated. "You of all people should know by now that the world is much bigger than most people think it is."

"I know it's a tough one to accept, but he's telling the truth," Ollie said to Malcolm and Nyssa. "Your Emerald Fighter may not have the same handsome face as me nor is he as friendly and charismatic, but we do have the same name and a shared penchant for archery and green leather."

"So you're another version of my husband from another universe?" Nyssa asked him.

"Wait, husband?" Ollie asked in surprise, before turning to Oliver. "This is your wife? Last time we were here, you were with Black Canary."

"It's a long story," Oliver simply said.

"I'm Chloe, by the way," Chloe said to Oliver. "Chloe Sullivan-Queen, your counterpart's wife." She held out her hand and Oliver shook it.

"This is Malcolm Merlyn, and this is Nyssa al Ghul," Oliver introduced the two to Clark, Ollie, and Chloe.

Malcolm turned to Clark. "What makes you so super, by the way?"

Clark turned to Ollie and Chloe. "Will you guys do the honors?"

"All right," Ollie nodded, before grabbing an arrow from his quiver and nocking it on his compound bow.

Chloe pulled out her gun from her left holster. "Do you mind if I use this in here?" she asked Oliver.

"Go ahead," he nodded, knowing exactly what Chloe was about to do.

"Just make sure you don't shoot me with that thing," Malcolm remarked.

"Don't worry, I'm just giving you the answer to your question," Chloe said.

Malcolm and Nyssa widened their eyes in awe as Superman levitated a few meters in the air. Chloe fired three bullets at the Man of Steel, while Ollie fired his arrow, which Clark effortlessly caught with one hand. The bullets bounced off of Clark's face and the arrow he was holding exploded without affecting him in any way, shocking Malcolm and Nyssa even more.

"That answers the question," Nyssa said.

"Consider me convinced," Malcolm added.

Clark descended back to the ground and picked up the three crushed bullets. Holding the bullets in the palm of his hand, he used his heat vision to incinerate them into nothingness. He then did the same thing to the pieces of Ollie's exploded arrow.

"Okay, now you're being a show-off, Boy Scout," Ollie remarked.

"Thank you guys very much for coming, I really appreciate it," Oliver said. "However, just to be completely on the safe side, I will be recruiting a few more people once we're on the island, but I'm not sure who to trust." He turned to Clark specifically. "So until a situation calls for it, I want you to hide your abilities."

"Wait, how will Clark know exactly when it's time for him to break out his heavy artillery?" Chloe wondered.

"By using his super-hearing," Oliver answered, before turning to Clark. "I need you to come up with a code word or a phrase that we could use as a signal."

"I got one," Chloe said. "How about 'Superman to the rescue'? Does that sound good to you guys?"

"We could use that phrase," Clark nodded.

"Perfect," Oliver also nodded.

"Well, I guess it's time for us to get this show on the road," Ollie said.

"Actually, in the air since we're flying to our destination," Oliver corrected.

(Morning)

Oliver was piloting the plane as Nyssa was seated in the copilot chair, while Malcolm, Clark, Ollie, and Chloe were behind them.

"So this is your island, huh?" Ollie said to his counterpart. "Any idea why this crazy Adrian Chase fellow would bring all your peeps here?"

"For that matter, how did he even know about this place?" Malcolm added.

"Talia," Oliver answered. "She researched me. Probably told Chase everything."

"Ironic," Nyssa said. "When I was a little girl, my father told me to visit this place. It's where I found Sara."

The plane swooped down, descending towards the island of Lian Yu.

(Lian Yu)

Laurel Lance blinked at the sudden sunlight hitting her eyes as a ninja removed the black bag from over her head before roughly pushing her to the ground. She looked around, noticing that she, John Diggle, Felicity Smoak, Thea Queen, and her father Quentin Lance had their hands bound in chains. The five of them were surrounded by a number of ninjas, one of the ninjas holding a sonic dampener that prevented Laurel from using her Canary Cry.

"Laurel?" Quentin said with concern as he noticed her.

"Daddy," Laurel replied. "Is everybody okay?"

"We're fine, little north of pissed off though," Quentin said.

"Roy, Rene, Curtis, where are they?" Diggle wondered, as he looked around for them.

"Not with us," Thea said, grimly.

She, Laurel, Quentin, Diggle, and Felicity all tensed as Adrian Chase, dressed in his Prometheus suit minus the hood and mask, walked over along with Black Siren, Evelyn Sharp, China White, Carrie Cutter, Liza Warner, and several more ninjas.

"Relax," Adrian drawled, with an insane smirk. "Enjoy the weather." With a chuckle, he looked at Laurel and said, "Ms. Lance."

"Go to hell, you bastard," Laurel snarled, right before a ninja suddenly put a sword to her throat.

"Get the hell away from her!" Quentin shouted angrily, only for another ninja put a sword to his throat too.

"Why are we here?" Thea asked, glaring daggers at their enemy.

"So you recognize this place," Adrian said. "That's good."

He turned around and started walking away as Siren, Evelyn, White, Cutter, Warner, and some of the ninjas followed him.

"Oliver's gonna come for us!" Thea exclaimed.

"Yeah, I'm counting on it, sis," Adrian replied, before he and his team disappeared out of sight.

"Sounds like Chase is using us as bait, he wants to draw Oliver out," Diggle said.

"Numbers aren't exactly in his favor," Quentin said.

"He faced worse odds before," Felicity said, optimistically.

"Yeah, but this time he doesn't have any of us to help him," Laurel pointed out.

"Laurel is right, Oliver can't do this alone," Diggle said.

(Underground A.R.G.U.S. Prison on Lian Yu)

Oliver opened the door and entered the prison with a duffle bag in his hand. He set the duffle bag on the ground near the entrance and slowly walked up to a cell.

After letting out a deep sigh, Oliver said, "I need your help."

"Hey, kid," the man in the cell – Slade Wilson – greeted with a chuckle before turning to Oliver. "I'm glad you came back."

Some of the dialogue and scenes in here draw inspiration from Aragorn II Elessar's fic "Thunder and Steel: The False God and The Madman" with his permission, so thanks to him for that.