A/N: Honestly, this was the most difficult thing to come up with an idea for. I did have trouble with day 9, but not like this one. Fortunately, I have all these kids lying around here so I decided to put them to use and have them come up with an idea for me. :) Seriously, though, if it weren't for my kids, I don't know what I would have written, probably some boring scientific piece. ;) My oldest used to watch Ben 10 as a kid so we have several videos and, currently, my youngest, who is autistic, is obsessed (no one obsesses like an autistic, I swear) with it so we've been watching it again. Which is why child #3 thought the episode "A Change of Face" from Season 3 of the first series might help me. And I hope you think it did. Child #3 has also decided he should expand on this story line and if he ever does I'll have him post it at AO3.
Title taken from the theme song from Ben 10.
"I can't believe this," 10-year-old Gwen Tennyson grumbled. "All I wanted to do was walk through Central Park."
She muttered her words of magic then sent a blast at Hex as beside her, her cousin Ben, the same age, turned the dial on the Omnitrix to choose an alien.
"Going hero."
Gwen heard Ben yell as he slammed his hand down on the device. This was followed by a flash of light. Out of the corner of her eye, Gwen saw that Ben had transformed into the giant, crystalline creature, Diamonhead.
Ben immediately shot a spray of diamond shards toward Hex and the sorcerer's niece, Charmcaster. The latter raised her hands and, with an incantation, turned the shards around and they headed straight toward Gwen.
Gwen raised her hands and quickly thought of a protection spell, but before she could utter one word, something collided with her and she was flying through the air. She realized someone's arms were wrapped around her and, before the two hit the ground, the other person shifted to take the brunt of the fall.
Her first thought was that it was her grandfather, but Gwen had never seen him move that fast. The person was moving them into a sitting position.
"Who are those people and what is going on?"
It was a man's voice and when Gwen turned toward him she thought briefly that his blond hair and blue eyes were familiar. But she couldn't place him so she shook the thought from her head.
"Hex and Charmcaster," she told him. "They want my cousin's Omnitrix."
She was about to explain the "watch" her cousin wore when the man guessed for himself.
"The thing that turned him into that creature?" he asked.
Gwen nodded.
"Steve!"
They both turned in the direction of the woman's scream.
Gwen saw a tall brunette, ducked behind the cover of a large round shield. Gwen looked up at her rescuer and back at the shield.
"You're Captain America," she gasped.
He only nodded, then grimaced as the woman with his shield was blasted backwards by one of Hex's spells. The he turned back to Gwen.
"You two handle the girl," he glanced over to where Ben was battling Chamcaster. "We'll take the guy with the ugly face."
Gwen nodded, relieved he didn't say something like, "Stay here and let the grown-ups handle it."
She watched Captain America run quickly to where the woman was trying to fight Hex, then Gwen ran to help Ben.
In a moment, though she thought maybe she should have suggested a different plan as Charmcaster had isolated them and contained them in her magic orbs. The sorceress placed one around herself then pushed Gwen's to the side to begin the spell that would make her trade places with Ben in order to gain control of the Omnitrix.
To her right, Gwen heard and saw some type of explosion, she suspected from a spell Hex had cast while battling Captain America and the woman who was with him. But she was too focused on trying to figure out a way to stop Charmcaster so she couldn't pay close attention to the other battle.
Gwen held her breath as she heard the final words of the incantation that would fulfill Charmcaster's desire. But just as the last word was falling from her mouth, Gwen saw two bodies fly across her view and into the orbs, displacing Ben and Charmcaster as the power of the spell took effect.
The orbs vanished and Gwen dropped to the ground. She looked up in time to see Hex fly over and grab a now screaming Charmcaster.
"Uncle Hex! You ruined everything."
But Hex only took her up and spirited her away.
Gwen watched as Diamonhead returned to the form of Ben and they both turned to look at the two adults on the ground who had come to their aid.
"Who are they?" Ben asked as he walked up to her.
Gwen looked at him, her worry had to be evident.
"They were Captain America and his girlfriend, I think," she said, and they both turned back to the couple.
A large blonde woman sat on the ground, shaking her head and looked over at a tall, but slender, brunette man.
"We are in so much trouble," Ben said.
Gwen sat on the very nice sofa in the Avengers Tower, wedged between her grandfather and cousin. On another sofa sat a woman who had been Steve Rogers, aka Captain America, and a man who had been someone by the name of Lieutenant Maria Hill. Or, Gwen supposed they still were those people, only not exactly.
"I'm still confused," a man's voice broke into her thoughts.
Gwen looked up at Clint Barton, aka Hawkeye, and saw a bemused look on his face.
"Yeah, can we run through that, again?" another man chimed in.
Gwen looked over at Dr. Bruce Banner, aka The Hulk. She figured she should be relieved at the grin he was trying to hide. At least he thought this was funny. Gwen suspected she wouldn't have liked it very much if he didn't.
"I just want to know how we're going to fix this," the strawberry blonde, apparently the only person living at the tower who was alone known by her own name, Pepper Potts, said.
"And how we're going to keep SHIELD from finding out," Tony Stark, aka Ironman, said from a stool at the bar.
"I can handle SHIELD," Gwen's grandfather spoke up.
Everyone turned to look at him, some with their mouths slightly agape in surprise.
"You can handle SHIELD?" Mr. Stark asked, and Gwen couldn't blame him for being skeptical.
But her grandfather only nodded.
"I was a Plumber," he said.
This comment garnered only raised eyebrows and confused looks from all the people in the room except one. Natasha Romanov, aka Black Widow, leveled a cool gaze at Gwen's grandfather and Gwen wondered if the woman really was as safe as everyone thought.
"I thought they were a myth," the redhead told Max.
He only shook his head.
"Nope, we're all real enough," he said, and he smiled.
Ms. Romanov turned to her friends and explained.
"Once, when I was in the Red Room, I interrogated a man who told me about the Plumbers. But the leaders in the Red Room said the man was insane and it was some sort of American myth," she explained to the other Avengers.
When everyone continued to stare at her Ben blurted out a more abrupt explanation.
"He battled aliens."
There was a collective pause in the room before each of the Avengers allowed themselves a groan.
"Of course, it would be aliens," Mr. Stark said. "What else could it be?"
To Gwen he seemed more exasperated than understanding.
"So Hex and Charmcaster are aliens?"
A woman's voice drew the attention of all in the room.
"Please, Cap," Mr. Barton said. "Don't talk. This whole thing is creeping me out enough as it is."
Within moments the rest of the Avengers were sharing a laugh. Even Ben joined in. Gwen failed to see the humor, having been switched once herself.
She glanced over to where, well, Gwen wasn't exactly sure what to call them now. The switch hadn't been exactly as it had when Charmcaster had made her first attempt. Something Hex had done must have disrupted his niece's spell. As a result, Captain America and Maria Hill hadn't exchanged bodies, they'd been changed themselves, to the opposite sex.
The woman who was Captain America was bright red with embarrassment. Gwen felt pity for her, or him, whichever the case was.
The dark-haired man next to him, no her, tugged on her sleeve and she leaned over as the man whispered something in her ear. Whatever he said caused a smirk to appear on Captain America's face, then he, Gwen shook that thought, she started to laugh.
With the man next to her joining in, the Avengers slowly abated and openly stared at the pair.
"I don't even want to know what she said," Mr. Stark mumbled.
"You mean, he," Ben corrected.
Mr. Stark stared at Ben for a moment.
"You know, kid, I like your style," the billionaire said. "Why don't I give you a tour?"
"Alright!"
Ben jumped up and followed Mr. Stark to the elevator.
"What about, well, this?" Gwen hollered after them.
"It's magic," Ben retorted. "You'll figure something out."
The doors of the lift closed and Gwen groaned in frustration.
"So this is magic?"
Ms. Romanov turned to Gwen who nodded.
"What did he mean by 'You'll figure something out?'"
"Gwen's somewhat versed in the magic arts," Grandpa Max said.
"So what do we have to do?" the man who had been Maria Hill asked.
"First, I have to figure out what spell Hex used," Gwen explained.
After about an hour of research with the help of JARVIS, Mr. Stark's computerized majordomo, Gwen was able to come up with something.
"I think Hex was actually trying to mess with Charmcaster's spell," Gwen said.
"That doesn't surprise me," her grandfather replied.
"What does that mean?" Captain America asked.
"It means it might be a bit more complicated than a simple reversal spell," Gwen explained.
"Can you do it?" Ms., or was it Mr. Hill now, asked.
"I think so," she said. "But it won't taste very good."
"Taste?" the group asked in unison.
"Well, part of it will require a potion," she informed them.
"Like 'eye of newt' stuff?" Ms. Potts asked.
Gwen furrowed her eyebrows.
"Sort of," she said.
"Well, just have JARVIS get everything for you," Ms. Potts told her. "Tony can pay for it all."
"Can pay for what?" the man asked as he and Ben re-entered the room.
"Magic stuff," Ms. Potts replied.
"Like rabbits out of hats?" he questioned.
"No, like gross 'eye of newt' stuff," Ben answered with a disgusted look on his face.
Gwen leveled a gaze at him that threatened pain but Ben just shrugged it off.
"Nice glare," Mr. Stark said.
"Sure she's not your long lost daughter, Red?" he asked Ms. Romanov.
He was rewarded with a bottle cap smacking him on the nose courtesy of Mr. Barton.
Gwen gave JARVIS the order, then Ms. Potts suggested Mr. Stark give Gwen and Grandpa Max a tour. They headed for the elevator along with the other Avengers, except for Captain America and Maria Hill, who opted to stay behind.
When the lift opened to the first R & D level, Gwen thought she might be in heaven. As Dr. Banner showed them around, she decided the Hulk's human side wasn't too scary after all.
Two hours later, they were having dinner in the Avengers' common lounge with a promise of games until the ingredients for Gwen's potion arrived. Captain America and Maria Hill returned to the group and sat opposite Gwen. She had definitely called it right, though they were engaged, which was technically more than boyfriend and girlfriend.
Gwen felt sorry for them. It must be kind of awkward, she thought, to see the person you're going to marry turned into another person. She tried to assure them that she had been successful with reversal spells before, though she didn't mention how limited her attempts had been. Fortunately, Ben was too busy regaling the Avengers with stories of the battles they'd been in and the aliens in the Omnitrix, and Grandpa Max was too busy making sure Ben's stories stayed within the realm of reality, where they were already wild enough without Ben's embellishments, to mention it themselves.
It was later that night when the materials for the potion arrived, by then Gwen was exhausted and Captain America told her she should get some rest before she started, assuring Gwen that they would be fine for a few more hours like this.
Mr. Stark put them up in guest rooms in the tower. Gwen was ecstatic to have her own room. Ben shared with Grandpa Max and, to Ben's chagrin, Mr. Stark listened to Grandpa Max when he asked to have a cut off time for the video games in the room so Ben wouldn't stay up all night playing them on the huge screen TV in their living room.
By 1am, Gwen wished it was as simple as turning off the TV and video games to get her to sleep. She finally got bored staring at the ceiling and went to the common room where she knew there was food in the refrigerator. She was surprised to find the very people she was worried about sitting together on the sofa.
Ms. Hill, or, well, Gwen was too tired to correct herself anymore, was asleep on the sofa, his/her feet in Captain America's lap. Gwen swallowed and waved nervously at the hero, the seriousness of the task ahead of her settling heavily in the pit of her stomach.
"Hey, Gwen," the female Captain America said with a smile.
"I couldn't sleep," Gwen said.
"Nervous?"
Gwen just nodded, though she hated to admit it. She didn't want them thinking she couldn't help them.
"Sit down, I can get you some ice cream or something," the super soldier told her.
Gwen sat. And as Captain America got her some ice cream with all the trimmings, they talked.
"You can just call me Steve," he/she said, and handed her a bowl full of ice cream, hot fudge, and whipped cream, with a couple of cherries on top.
"Thanks," she said.
"It's OK if it doesn't work. The spell, I mean," Steve said.
Gwen gave him a worried look.
"Really," he/she went on. "If worse comes to worse, maybe we can get Thor to give us a hand."
Gwen only nodded. She didn't want to think about the possibility of failure.
They talked some more about her travels with her cousin and grandfather. Gwen wanted to know about Steve's work with the Avengers and, more importantly, how he and Maria had become engaged. She thought it was a very romantic story and was glad they'd talked about it now, without Ben being present. He was sure to be grossed out.
Finally, Gwen had finished her ice cream and felt her eyes struggling to stay open. Steve chuckled and helped her up and to her room.
The next morning came early, but Gwen was up and in the lab (for safety reasons) mixing up her potion. Dr. Banner was asking her questions about her magic, while Steve and Ms. Hill sat quietly holding hands and watching. Mr. Stark finally showed up with Ben and Grandpa Max in tow. The rest arrived shortly after that.
Finally, everything was ready.
"OK," Gwen said as she poured two cups worth of the grayish-green liquid.
She handed the couple the glasses and told them to drink.
They exchanged looks then Captain America leaned down and whispered something in his/her fiancées ear causing the Lieutenant to blush. Then, in unison, they swallowed down the potion. Ms. Hill made a face, but Captain America commented that it tasted like castor oil.
"What's 'caster oil?'" asked Ben.
"It was a medicine I had when I was your age," Steve replied.
Gwen took a deep breath, and was grateful everyone on the room had fallen silent. She was nervous enough without background noise to distract her. She'd never live it down with Ben if she left Captain America in this state.
As she began to say the incantation, the two pink orbs formed again and surrounded Captain America and his fiancée. Then Gwen started the words of transformation. Each of the orbs began to glow until their inhabitants were hidden from view due to the light.
This was stronger magic than she was used to handling and shortly Gwen began to tire. She felt someone gently pick her up and place her in a chair as she continued. Then, with a bright flash, the orbs disappeared and the two people inside dropped to the ground. Gwen smiled as she viewed her success, then she, herself, began to fall forward out of the chair.
"Back up, back up, give her some room to breathe," Gwen heard a voice say.
As her eyes slowly opened she found herself on a cot, surrounded by the Avengers and her cousin and grandfather. She almost smirked as Ben tried to act as if he wasn't concerned at all, but her head hurt too much.
"Did it work?" she managed to squeak.
"Yes, it did," the man's voice she'd heard earlier at the park said.
She smiled and glanced over to see Captain America and Maria Hill, restored to their old selves.
"That's a pretty neat trick," Dr. Banner put in.
Gwen tried to reply but her throat was too tired.
"Think you can manage to get to your room?" Ms. Potts asked. "The bed is softer and far more comfortable."
A woman's hand took hers and helped her up. Gwen looked up to see Ms. Romanov above her, an actual smile on her face.
She looked around the room at the Avengers team as she slowly stood, supported by none other than the Black Widow, and she thought that of all the adventures she and Grandpa Max and Ben had had over the summer, this was by far the most unexpected.