So way back in the last days of 2016, I pitched an AU for the Flash where Caitlin was Vibe and Cisco was Killer Frost. kineticallyanywhere (whose art of Killer Frost!Cisco you should totally check out because it's mindblowing) ended up doing fanart, and through a bunch of messages we created a universe for this. I ended up writing something for it, and it won't be the last of this alternate reality either.
This one takes place in S2 E19, but instead of Caitlin, Cisco was kidnapped.
As soon as Zoom was gone, Cisco finished picking the lock on his shackles. When they fell away with a clang, he sighed in relief, rubbing his wrists. Zoom had put them on tight, and they'd been starting to hurt. At least he was free from them though. Now, he could snoop around and see if he could find anything to show what Jay, or Zoom apparently, was up to now.
Hopping off the cot he'd been shackled to, Cisco started to explore the lair. It really did suit an evil speedster. Everything felt dark and grimy, and that was without including the shackles and barred cells. He felt bad for Jesse Wells. She'd had to stay there for months in this place with Zoom taunting her.
The sound of tapping drew him towards another area of prison cells. These ones didn't have bars, but a thick plate of something transparent enclosing them. Cisco had a feeling they might block meta abilities. Approaching the cell closest to him, he saw a man in an iron mask seated on the ground. He kept tapping on the glass in short random bursts, although Cisco wasn't sure what it was supposed to mean. It definitely wasn't Morse code, or the Earth-1 version of Morse code.
"Hello?' he tried, stepping close to the front.
The man in the iron mask straightened up and began to tap more.
"Well, isn't this a surprise?' an icy voice sneered behind him.
Cisco whirled around to face the cell behind him. Emerging from the shadows was himself, or at least his Earth-2 doppelganger. Caitlin had told him all about Killer Frost after she and Barry had returned from Earth-2, but he had never known what his double looked like until now. Icy blue eyes and white hair pushed away from his face were the physical differences that jumped out at Cisco immediately. While Cisco was wearing jeans and a Star Wars t-shirt under his jacket, Killer Frost was dressed in a dark blue jacket, black pants, and had a blue scarf fashionably draped around his neck.
The engineer raised a finger, stunned at the sight of himself on another Earth. "Doppel-"
"-ganger?" Killer Frost finished. "You must be the Cisco Ramon your pretty little friend Caitlin wouldn't stop talking about."
"And you're Killer Frost," Cisco murmured, taking a step forward.
Frost's smile was cold. "So we finally meet."
On the other side of the glass, Cisco sucked in a deep breath. "So what are you doing here?"
"Zoom decided not to kill me when he found out I helped your breacher buddies," he sighed. "Instead he shut me up in this box instead. Now, I have to sit here every day listening to that IDIOT WHO CAN'T STOP TAPPING!"
Behind them, the man in the iron mask ceased tapping.
"First time he's finally shut up," Frost smirked. "Although as soon as you get me out of here, I'm still freezing him."
"Wait, hold on," Cisco held up both his hands. "I said nothing about letting you out. Why would I even let you out? Can't you do that yourself?"
"Think I'd still be here if I could?" the double snapped, gesturing to the glass. "Carbine walls won't let me freeze a way out."
Cisco nodded. "Fair enough. Still, why should I let you out?"
"Because I know you want out of here too," Frost replied. "And I could get you an escape off of this rock. Unless, of course, you'd rather jump off the cliff."
Cisco weighed his options that stood before him. The most preferable outcome of any of this would be able to keep his evil double in the cage and get down the cliff on his own. But a quick trip to the edge and getting a look at the drop from it had him reconsidering Frost's offer. His double might be evil, but right now, letting out the Ice King might be the best plan of action to start finding a way back to his own Earth.
"So what's your move?" Killer Frost asked when Cisco walked back to his cell.
Cisco stopped in front of the carbine glass. "You swear you'll get me out of here once you're free."
"Deal," Frost agreed.
Cisco breathed a sigh. "Okay, let's stage a prison break."
It took a while before Cisco formulated a plan to get his doppelganger out of the cell. After he got an idea, he set to work immediately. If he heated up the carbine walls of Killer Frost's cell with an electrical current, the molecular structure would be weakened. Frost would then be able to freeze the carbine, and all they'd need to do to free him would be to break it.
Killer Frost listened to Cisco's explanation with a bored expression, as if he wasn't paying attention. Still, the doppelganger watched him intently as he collected the materials. It was a little unnerving to be watched by himself, even though there were obvious differences in appearance. Still, Cisco pressed on, knowing there was only so much time they'd have before Zoom returned.
"Are you even close yet?" Frost drawled out as Cisco lugged the wire towards the cell.
"Hey, I'm going as fast as I can with all your help," Cisco snapped. "And you know, I could just leave you in there, Elsa."
Frost smirked. "But then you've got no way out of here. I'm your way down, remember?"
The scientist sighed and rolled his eyes. Maybe he should change topics. "So how'd you become…this?"
"I woke up like this one morning," Frost shrugged. "My blankets were frozen around me. The floor was coated with frost. It looked like winter had hit the room. I felt cold as ice, and figured I was sick. Then I realized that…I was better than ever."
To emphasize his point, his hands turned blue and white mist spilled over them onto the floor. Cisco could hear a crackle of frost through the carbine as Frost flexed his fingers. A chill went down his spine at the action. For a minute, he wondered if that could have been him if the accelerator had affected him.
"The dark matter from the particle accelerator hit you," Cisco gulped as he set the wire down. "It made you into a metahuman."
"Bingo," Frost snapped his fingers before his nose wrinkled. "Happened a few weeks after I got kicked out of my doctoral program. I was lucky that my brother let me stick around and sleep on his couch."
Cisco snorted. "That must have been fun if he's anything like the Dante I know."
Frost actually looked surprised at his sarcasm. "You and Dante don't get along on your Earth?"
"He's always been the golden boy," Cisco grumbled. "I could never live up to his standards, at least not for my parents to be happy."
"Used to be like that once," his chilly double remarked. "But we both became the family disappointments. It brought us together. When this first happened to me, he was the only one who didn't flinch at what I became. He'd been changed too though, even if it wasn't visible. We knew we had to stick together after it. Eventually, Reverb found us, and she made sure the city truly feared us. Now that she's gone, Dante and I can get full reign on the city once you get me out of here."
"Fantastic," Cisco muttered, shaking his head. "I'm about to let a criminal loose."
It didn't take much longer before the carbine was heated up. Frost froze it over, and Cisco took a sledgehammer to the iced over space. After the frozen shards rained down onto the floor, Killer Frost stepped out of the cell. Cisco watched as the villain flexed his wrists as cold mist rolled over them again. The air around Cisco felt like it lowered a degree or two. Meanwhile, he stepped toward the other cell, the one that held the man with the iron mask.
"We should do something about him," he announced. "I'm not leaving anyone with Zoom."
"Oh Francisco," Killer Frost sighed. "That soft heart of yours…it's going to be your downfall."
Cisco whirled around to see Frost raising his hands, ice forming over them.
"Hey, we had a deal!" he shouted. "I get you out, you get me out!"
"You seriously fell for that?" Frost rolled his icy blue eyes. "How naïve is your silly little Earth anyways?"
He threw his hand forward, and Cisco ducked an icicle.
"Now, Cisco, I did say I'd get you out of this," the other man sneered, more mist trailing through his hands. "Unfortunately, it won't be down that cliff."
That was when Cisco started running. He took off towards where he had been chained up by Zoom. It wasn't very long before his feet suddenly skidded and he landed hard on ice that hadn't been there a few seconds ago. He slid into a pile of random junk with a crash, instinctively curling up as things fell on top of him. When he was able to climb to his feet, Cisco saw Killer Frost stalking towards him.
"I don't know why Zoom brought you here," he taunted, a sharp icicle forming in his hand. "But he's kept me locked up long enough. He took my freedom, now I'll take something that he wants."
Frost threw the icicle towards his chest. Cisco froze as it sailed towards him, even though his brain was screaming at him to move. Before it could pierce his chest, Zoom appeared. The next thing he knew, Cisco was staring at his doppelganger hunched over and held up by Zoom. The icicle that was supposed to hit him was now impaled in Killer Frost's chest. He didn't realize it, but Cisco put his hand to the exact same spot on his chest where Frost had been stabbed, as if he could somehow feel it too.
"I spared you once," Zoom rumbled. "I won't again, your brother's wrath be damned."
He let Killer Frost drop to the floor. A moment later, Cisco was back in the shackles, with Zoom standing over him.
"You were a fool to do that," the speedster growled. "He could have killed you."
"You want a thank you?" Cisco muttered, glaring at the man he once considered a friend. "You're not getting one. Not unless you get me home, and even then I'm not sure I'm going to give you one."
Zoom chuckled. "Soon, home is all you will have left. And you're going to help me."
"Why would I do that?"
Zoom looked back at where Killer Frost's body was crumpled on the floor and pointed a clawed finger towards it. "If you don't, then I will kill everyone you love in front of you. Your family. Your friends. Anyone you care about."
Cisco swallowed, unable to stop himself from picturing Dante with Zoom's hand vibrating into his chest. Then it was Barry, Joe, Iris, Harry, Caitlin. He couldn't let that happen to them.
"So what do I have to do?" he swallowed, pushing the terrible images aside.
Zoom was probably smiling underneath his mask as he sped away and returned with a few blueprints. He instructed Cisco to take a look at them, and to tell him what could be done to reduce time on the project.
A sinking feeling settled over Cisco as he looked at the schematics for what seemed to promise destruction for other Earths.
There's likely to be another fic in this series where Caitlin discovers her powers and becomes Vibe.
Hopefully you all enjoyed this!