Chapter 1: Dr. Jekyll and Mrs. Hyde

AN: I began planning for this story back when Season 3 was still airing and am just now getting around to posting it. The Savitar/Killer Frost dynamic was just so intriguing to me. I wish they'd done more with it, so I wrote my own story to fill the void. I know I'm several years late to the Season-Three-rewrites-party, but this idea has stuck with me for so long. I finally decided to stop overthinking everything and just put it out there. Also, quick side-note: this story IS NOT Julian-friendly. I had many issues with his character that will be brought up in this story. If you're a Julian fan, I'd turn back now. There's also some WestAllen in here, but it's far from the focal point. I think this story will satisfy both WestAllen and SnowBarry fans in their own ways.

Anyway, that's all I've got to say. Enjoy!

He didn't even have to look up to know she was watching him. The sudden chill in the air gave her away.

"If you're gonna stand there all creepy, why don't you do it where I can see you?"

Killer Frost slid out of the shadows. She confidently strode toward Cisco's work table, curtly asking, "Are you finished yet?"

"Yeah well, if I was, I wouldn't be so quick to tell you," he replied, looking up from the Speed Force Bazooka. "What, you don't think I don't know that I'm dead the second I finish this?"

She began to circle him, like a lion stalking its prey. "You know, there's a way you can save yourself."

"How do I save myself, pray tell?" Cisco asked dryly. He never ceased to interject some sarcasm, even in the direst of situations. Iris has made many disapproving remarks about his sardonic sense of humor.

"By joining us," she said, not missing a beat.

"Wow – I suppose this is the part where I join the dark side, then?"

"Come on. Savitar, Killer Frost, and Reverb – you remember what Reverb told you on Earth Two. You have the power to become a god."

"Is that what Savitar promised you?"

Killer Frost casually leaned against the table, as if she were talking to an old friend instead of her captive. Cisco felt a pang in his chest at how familiar the gesture was. "You have so much potential. And trust me, it's so much more fun to be bad."

"I know you don't really think that." Cisco took a brief pause, choosing his next words carefully. He wasn't sure whether sharing this information would make things worse or better. Either way, he supposed, she had a right to know. "Julian went to Tannhauser to work on a cure – with your mother. He figured it out."

The cocky look on her faced dropped in an instant. She removed her elbows from the table, straightening her back. "You're lying."

"Your BFF just told me so."

Killer Frost briefly bowed her head, unable to maintain Cisco's piercing eye contact. He had no idea what she was thinking, but the fact that he got her thinking at all was a victory in itself. Perhaps this was the chance he needed to break through to her.

Cisco took a step closer. "It doesn't have to be like this. We can fix you." Killer Frost then restored eye contact, so he was encouraged to add, "Come back to us."

Once he said that, the skepticism on her face abated. Her icy-white iris's flared in anger. "Fix this," she spat, "Or I'll show you who I truly am."

Killer Frost gave him one last chilling stare before striding away. She had almost exited the room when a familiar whoosh stopped her in her tracks.

"How did it go?" she asked, turning around to face whom she thought would be Savitar. Instead, Killer Frost was met with the faces of Barry and Wally. Instinctively, her hands flew up, frost appearing from her palms. "What do you two think you're doing here?"

Barry's hands rose as well – but in a sign of surrender. "Hey, there's no need for that. We're not here to fight. We came to bring you home." He glanced over at Cisco and smiled. "Both of you."

Cisco smiled back, relief clear in his voice. "Man, am I glad to see you guys."

"Are you insane? He's not going anywhere," Killer Frost sneered. "And you two are gonna have to go through me before you can even hope to walk back out." One of her arms pulled back, getting ready to fire.

Barry stretched his arms out even further, emphasizing his gesture of peace. "Caitlin, wait! You don't have the full story. Savitar – he..." He floundered for the right words, eventually turning to his protégé for help. Kid Flash just gave him a skeptical shrug. Barry sighed, relenting to telling the straightforward truth, "We met up earlier, and I convinced him to come back to STAR Labs. The Team is trying to find a way to keep him from, you know..."

Wally made a boom sound with him mouth and used his hands to mimic an explosion. Cisco tried to hide a snicker.

Killer Frost looked surprised for a moment, but it soon faded into distrust. "You never were a good liar, Flash. The last thing Savitar would do is turn to you guys."

"Caitlin, I promise, this isn't a trick-"

The frost at her fingertips accelerated. "Stop calling me 'Caitlin'! That is not my name."

Barry swallowed hard. He took a cautious step forward, as if approaching a wild animal. There really wasn't much difference, after all. "I'm not calling you 'Killer Frost'. I know you; you're no killer."

"Come any closer and we'll find out."

"Come on, Caitlin. We wouldn't have even known where to find you if Savitar hadn't told us," Wally finally spoke up.

That statement seemed to make her stop and think. Barry seized the opportunity, speaking again, "He's agreed to accept our help. We can help you, too. At least come back to STAR Labs – then you can talk to Savitar yourself. And if you choose not to stay, we won't stop you."

Killer Frost looked right into Barry's eyes, searching for deceit. After a minute, her own eyes narrowed. "Fine, I'll go. But if this turns out to be a trick, you will regret it."

Barry nodded. He quickly directed Wally to take Cisco, while he took hold of Frost's arm. She flinched under his touch but didn't pull away. The next thing she knew, Barry took off, racing her though the city.

The Cortex was quiet when they arrived. The atmosphere reeked of exhaustion and grief; she could practically smell it in the air. Those were feelings so well known by Team Flash. Frost remembered many occasions where she, herself, was too distraught to even move. It was almost nostalgic. She was so well-acquainted with sorrow, so accustomed to the emotion that it was almost a comfort being in the midst of it again. She never imagined that she'd be the one to create it, though.

Barry halted to a stop in the middle of the room, and Killer Frost quickly yanked out of his grasp.

Almost immediately, she heard a British voice behind her call, "Caitlin!" Killer Frost turned around to face Julian. His expression was one of pure, unfiltered relief. Julian smiled at her like she was the answer to all his prayers. "Thank goodness you're okay."

No such joy was found in her. Julian was the last of her concerns right now. She ignored his comments and instead faced Barry to ask, "Where's Savitar?"

He pointed over her shoulder. "Med bay."

Killer Frost stalked away, ignoring the feeling of Julian's eyes burning into her back. She entered the med bay and looked around to locate the self-proclaimed God of Speed. True to Barry's word, Savitar was sitting there at one of the desks. Her blood ran that much colder seeing him here. A part of her had hoped that this was a trick. At least then, he wouldn't have been abandoning their plan without so much as a word to her.

"Mind explaining to me what's going on?" she demanded, skipping the greetings.

He swiveled around in the chair to face her. "Good – you're here. I should tell you there's been a change in plans."

"Oh, now all of a sudden you want to keep me informed? I already figured that out when Barry and Wally came bursting into the warehouse."

"So, you don't need an explanation, then?"

Killer Frost decided to ignore his blatant sarcasm. She was in no mood for his smart-aleck mouth. "Why would you tell them where Cisco was? He had almost finished the Speed Force Bazooka."

"I may not need it anymore."

She scoffed. "What would make you say that?"

"I'm sure Barry told you. They're going to fix my problem for me."

Killer Frost paused, somewhat taken aback by his response. Her tone was disparaging when she finally spat out, "And you believed him?"

Savitar looked down at his fingernails, sighing. "It's complicated, alright?"

"I'll bet it is. Savitar, we already havea plan to keep you in existence. Not only that, but to make you a god. Why are you throwing that away – especially for Team Flash, of all people?" She spat out the words "Team Flash" like poison.

Killer Frost would be lying if she said her anger was directed solely at Team Flash, though. She was also quite offended that Savitar seemed to have lost faith in their plan – or, even more offensive, lost faith in her. Did he not believe that she could fulfill her end of the bargain? Did he think her to be weak? There had to be some explanation for his sudden turn around. Team Flash must've been an excuse. Surely he didn't trust them. Killer Frost had spent way too many an hour listening to him vent about how cruel Future-Team Flash had been.

It made her blood boil just thinking about it. She had stood by Savitar, even after their initial plan went awry. He had been beaten, neglected, rejected, but she was still willing to work with him. Savitar wasn't very trustworthy, but he wore the face of someone she'd once trusted, so that had been enough for her. And most importantly, she accepted him – something that Team Flash certainly hadn't done.

Despite all that, this was how he repaid her loyalty? By ditching her?

"It's better this way."

The small flurry of anger in her stomach turned into a full-blown snowstorm. "For who, Savitar? It certainly doesn't benefit me, so are you just thinking about yourself?"

Savitar glanced up at her, silent. His eyes were dull and emotionless, but she knew better.

Frost shook her head slowly, giving him a nasty look. "So that's how it is? You get a better opportunity, an easier way out, and you just bail on all our hard work?"

"I don't have to justify my decisions to you."

"Unbelievable. How very Barry Allen of you. Once again, you couldn't care less what happens to everyone else as long as you get your happy ending."

"You call this a happy ending? I spent decades perfecting this plan! For so long, I had a guaranteed win. In the future, I was a god. Then that drumstick-carrying buffoon ruined everything!"

"Oh, cry me a river! We both know why you did this. You've spent so much time trying to prove how opposite you are from the Flash, but you're more selfish than Barry ever was."

If she hadn't been so angry in that moment, perhaps Killer Frost would've noticed the thinly-vailed pain in his eyes. It was a low blow, comparing him to Barry – and she knew it.

The pain wasn't there for long, though. It disappeared in an instant, replaced with his usual hateful expression. "And what is it that I'm so selfishly keeping you from? Huh? What do you want from me?"

"You weren't the only one who gained something from this, Savitar. I had stakes in this plan, too! What makes you think I don't still want to rule this city?"

The closest thing to a chuckle escaped his mouth. "You think you could accomplish that alone? Fine! Have at it! No one ever said you had to stay here. If you think you can do better, go. I'm not stopping you. I made my decision, and you are more than welcome to make a different one."

"I don't need your permission, Savitar. You are not my boss. We were partners. Partners decide things together. Partners look out for each other."

"Well, I don't know what to tell you. Partnerships end, alright?"

Hearing him say that bothered her in a way she couldn't explain. Her hands were beginning to shake after all that yelling, but she refused to let it seep into her voice. "Fine. If that's how you feel, maybe I will go off on my own."

She turned and marched out of the room, not giving him a chance to retort.

Team Flash stood around the winding desk in the Cortex, secretly eavesdropping on to the fight going on in the Med Bay. However, their entertainment was cut short when the commotion suddenly stopped. Killer Frost came out soon afterward, walking right past them wordlessly. She brushed past Iris and Joe, who happened to be entering the Cortex as she was leaving.

Joe looked back at her retreating form. "What happened?"

"Dr. Jekyll and Mrs. Hyde just had a domestic," Cisco commented.

Wally chuckled from where he sat at the desk. Iris, however, sent Cisco a disapproving glare.

"This is no time for jokes, Cisco," she said.

"A: that wasn't a joke. B: I just spent the better part of the night being the assistant to Frankenstein. Let me have this."

Iris rolled her eyes. Joe decided to step in, saying, "We're not just going to let her walk out again, are we?"

Cisco looked out into the hallway, letting it sink in that Killer Frost had just stormed off. A bit of anxiety developed in the pit of his stomach. Joe was right; they couldn't afford to lose her again. This was, perhaps, his last chance to get his friend back.

With a nod, Cisco said, "Leave it to me," and jogged off after her.

Once he was caught up to her, he slowed down to match her pace.

She glanced his way but didn't falter in her stride. "Oh, wow. Is the great Cisco Ramon about to grace me with one of Team Flash's famous 'hallway heart-to-hearts'?" Every word dripped with sarcasm.

"Hey! I'll have you know, my pep-talk game is very strong." Killer Frost just gave him another sidelong glare, but he could tell she was amused. Softening his tone, he asked, "But, for real, are you alright? That fight sounded intense."

"What do you care?"

"What do you mean, 'what do I care'? I care about you, Caitlin."

She scoffed. "Yeah, right."

"It's true. Come on, Cait, we've known each other for years. You know I'm always gonna look out for you."

"For the last time, stop calling me Caitlin! I'm not Caitlin! Quit pretending like you're so worried about me. I can watch out for myself."

Cisco stopped, grabbing hold of her arm. She stopped also, if not just to yank her arm away. "Is that what you think – that I only care about you when you're Caitlin?"

"Don't play dumb, Cisco. All the offers you've made to 'help me', to 'cure me', to 'fix me' - it's clear you only want Caitlin."

"What? No! That's not why I said those things. I said that because I know how afraid Caitlin was of you, of becoming you. And I don't believe that you're happy like this, either. I just wanted you to know that you have options. Working with Savitar wasn't the only way to go."

She chuckled humorlessly. "Yeah, well, it certainly isn't an option anymore."

"There is still another one."

Killer Frost looked at Cisco skeptically.

"The cure," he elaborated. "Savitar wasn't lying. Julian told me himself that he worked out a remedy. It's yours, if you want it."

"What makes you think I'm not happy like this?" she asked defensively.

"Are you happy like that?"

"Contrary to popular believe, Cisco, my life is not all that bad."

"That didn't answer my question."

Killer Frost huffed, looking away in frustration.

"Look, I just don't want you to settle because you don't think there's a way out. We have a cure, Frost – a legitimate cure. You can have your old life back."

"Assuming that the cure actually works."

"You'll never know unless you try."

Killer Frost paused for a long moment. The fact that she was considering this at all surprised even her. Most days, she would've scoffed or cringed at the thought of being Caitlin again. Even now, it seemed a bit unsettling. She'd been fighting for control for so long. Would she really be willing to give it all away in an instant? Was she better off as Caitlin Snow? Being Killer Frost certainly had some perks. She was more confident, more composed, more powerful. As of right now, however, she was also more alone.

The threat she made a minute ago about going out on her own held little-to-no weight. Even Killer Frost recognized that. By nature, she was a social person. She'd worked in groups all her life. From her high school newspaper to her job at STAR Labs to her position on Team Flash, she always worked with others. Now that her partnership with Savitar was over, though, she felt quite directionless. Caitlin never thought anything worth doing unless she was doing it with others. Unfortunately, Killer Frost inherited that sentiment. She simply didn't know how to function 100% on her own. All her life, she had never had to.

That said, maybe she would've been better off as Caitlin. At least Caitlin would be happy to reunite with her team. After all, Killer Frost no longer had anything to strive for. Her alter ego still had a chance, though – a chance to be part of a group again.

There was one thought that still nagged her, though. Even if she did take the cure, there was no guarantee that Caitlin Snow's life would be exactly the same. After all the time she's spent in control, after all she's done, Killer Frost doubted that her alter ego would return unscathed. At this point, too much had happened. The girl that Team Flash so desperately wanted back just might not be the same anymore.

"Cisco, you do understand that even if Caitlin returns, that doesn't mean that my life will go back to normal – right?"

Cisco was quiet for a moment, contemplating her words. Killer Frost bit her bottom lip in anticipation. Finally, Cisco replied, "Yeah, I understand that. It doesn't matter, though. All I want is for you to be as happy as possible. If that's as Frost, then so be it. But if it's as Caitlin, then I hope you'll give it a chance. Whoever she is now, whoever you are now, I'd welcome her any way – as long as she's happy."

Now it was her turn to think quietly. Killer Frost couldn't help the relief she felt at Cisco's words. If Team Flash truly was willing to give her another chance, maybe she could meet them half way. Maybe. There was still a lot to consider. After all, Caitlin had never done anything for her, so why should she help her? She didn't owe Caitlin anything.

With a long sigh, she finally relented. "I'll think about it."

Cisco's expression lightened, his eyes filling with hope. "That's all I'm asking."

He removed a vial full of blue liquid from his pocket and offered it to her. She glanced at it, then shook her head. Cisco's eyebrows fell in confusion, but he pocketed the cure anyway. While he did that, Killer Frost began walking away again.

"Hey, where are you going?" Cisco called after her.

"Home," she answered simply, pressing the button for the elevator. "I told you: I need time to think."

"You're more than welcome to stay here, you know."

Killer Frost stepped through the opening doors. "Don't worry your pretty little head, Cisco. I won't go out and start another Ice Age or anything."

Cisco chuckled. "That's not why I was offering."

"No, of course not," she replied sarcastically.

The elevator doors closed, leaving Cisco alone in the corridor. In spite of himself, he smiled a little. Despite all that's been going on, he saw a small sliver of light on the horizon.

He turned and walked back to the Cortex. Once he arrived, Cisco saw Harry talking quietly with the other members of the team. No one seemed to notice his entrance.

"What's up?" he asked.

"Cisco," Iris said in surprise, turning to face him, "How did it go with Caitlin?"

"It went well, I think. I have a feeling she might come back to us," he said.

There was a collective sigh of relief and expressions of joy amongst the team.

"So, she agreed to talk the cure?" Julian asked hopefully.

"She's going to think about it," Cisco admitted. "But I really think I got through to her."

Many in the group nodded, all trying to take in this new information. It was a small victory – but a victory nonetheless. Caitlin was a core member of their team, and her absence was felt profoundly. The prospect of having her back was a heartwarming one for them all.

Cisco made to change the subject. "So, as far as our other guest is concerned, what have we decided?"

"Well, you'll be happy to know that Tracy has agreed to help," Harry said.

Cisco nodded. "Well, that's something."

"Speaking of which," Barry said, "Savitar's on borrowed time; we need to start figuring this out."

"Tonight?" Wally whined. "Look, bro, I know this is important and all, but some of us have classes in the morning."

Joe gave Barry a pat on the shoulder. "It's been a long day, Bar. Maybe it would be best if everyone went home and got some rest before trying to defy the laws of physics."

Barry let out a tired sigh, nodding. "Yeah, you're probably right, Joe."

"What about Savitar? We can't leave him here all night without supervision," Julian said.

Barry looked around at his friends before shrugging. "I guess I'll stay and pull a graveyard shift. Keep an eye on him."

"Well, if you're staying, I'll stay, too," Cisco offered. "That way we can take turns staying up."

Normally Barry would've tried to argue, to insist that he could handle it alone. However, it had been a long night. He was tired – physically and emotionally – and now wasn't the time to play the hero. Literally. So, instead, he smiled gratefully and said, "Thanks, Cisco."

"Alright, well, be safe – both of you," Joe said, giving the heroes his fatherly, no-nonsense look.

Cisco smirked. "Come on, Joe. How much trouble could we possibly get into?"

"I'm serious, you two. Savitar may have backed down for now, but he's still a threat – not to mention unpredictable. Do not lower your defenses." More softly, Joe added, "We already lost one person tonight. I'm not losing anyone else."

Barry nodded solemnly. "We'll stay alert, Joe. We promise." Cisco simply nodded his consent.

"Alright, well, I guess I'll see you guys in the morning," Iris said, looking sadly at Barry.

After all this time wondering if she would live to see their wedding day, Iris never wanted to leave Barry's side again. They won tonight. They stopped Savitar. Yet, there was still this fear within her that Barry would be ripped away from her. The last thing she wanted was to leave him – and for the entire night, no less.

As if Barry could read her mind, he pulled her in for a comforting hug. Iris immediately wrapped her arms around him, burrowing her head into the crock of his neck. Barry rubbed her back soothingly and murmured into her hair, "Don't worry, Iris. We'll be fine. No one's gonna take you away from me anymore."

He felt her nod against his chest. They lingered in each other's embrace for a minute more before breaking apart.

Despite Barry's assurances, Iris was still inclined to ask, "Maybe I should stay, too? You guys might need the extra help."

Barry gave her a fond smile but shook his head. "We've got it covered. You should go home and get some rest."

Iris nodded resignedly, trying her best to return Barry's smile. Though she doubted sleep would come easily, if at all. She reached up to give her fiancé a peck on the cheek before leaving with Joe. Once the rest of the team said their goodbyes as well, Cisco and Barry were left alone in the Cortex.

Barry then turned to Cisco. "I better show Savitar to one of the spare rooms."

Cisco nodded, dropping into one of the desk chairs.

Barry made his way into the Med Bay and found Savitar sitting in the same chair he was in half an hour ago. He knocked on the doorframe. Savitar looked up.

"We're shutting down for the night, so... you can take one of the spare rooms. If you're tired."

"Oh, sure. There's a huge threat of, you know, disappearing from existence hanging over my head, but I'll try to sleep."

Barry sighed. "Do you want the room or not?"

Savitar blinked once, twice, then rolled his eyes and stood. Barry assumed that, despite what he said, Savitar must've been tired. Otherwise, he would've fought much harder to think of a comeback. Barry didn't dwell on it, instead leading the way to Savitar's room.

The walk down to the lower floor was about as awkward as one could imagine. There were two versions of Barry – one selfless and heroic, the other broken and twisted – walking side-by-side. They were the same and yet different; familiar and yet strangers. After everything that had transpired today, it didn't seem like there were any words to be said. At this point, Barry didn't think Savitar was worthy of a conversation. Too much had happened. Too much would've happened.

When they finally reached Savitar's room, Barry stopped in the open doorway. Savitar stopped, as well.

"Here we are," Barry said gesturing into the room.

Savitar took a peek inside. "Wow, look at that. I have a bed and everything. Wouldn't you rather throw me in the Pipeline?" he asked dryly.

"I might," Barry said seriously. "Look, Savitar, you're a guest here. And we will do everything we can to help you. But if you step out of line-"

Savitar sighed in annoyance. "You don't need to read me my rights, Barry. This isn't my first time being 'The Broken Time Remnant'."

"Hey, I never said that."

"Yes, you did," he said simply. "Six years from now."

Savitar stepped into the room, looking around in more detail.

Barry stood there a minute, waiting to see if Savitar was going to request anything additional. It seemed too friendly, too cordial to offer him anything other than a bed. Ultimately, they'd won today. Iris was safe, and Cisco had gotten through to Caitlin. However, they still lost a teammate. H.R. was gone, and this was no time to be courteous to the man who killed him.

When it was obvious that Savitar wasn't going to speak anymore, Barry turned to leave. "Sleep well," he said, more out of social convention than sincerity.

Savitar didn't respond, but Barry wouldn't have heard anyway. He shuffled to the far end of the room to lay down on his bed. Hours ago, he was the God of Speed. Now, he was just Barry Allen's time remnant, alone in a dark room.

It wasn't anything he wasn't used to.

AN: Also, just an FYI, that scene between Killer Frost and Cisco at the beginning isn't mine. The dialogue is copied verbatim from a deleted scene I saw from 3x23. I thought it was a good way to start my story. If you're curious, you should try to find it. The scene itself sheds light on a lot of things - at least I think so.