A husk, tall enough to touch the ceiling, is sitting in S.T.A.R. Labs. Amidst the chaos of Barry being attacked by an invisible speedster, Wally grabbed Alchemy's stone. When he did he was immediately enveloped in a cocoon.

"Guys, I know this is bad," Cisco says, "but it's kinda cool."

"No, it's not," Joe snaps.

Cisco leans over to Caitlin. "It's really cool."

"What do we do, Bar?" Joe asks.

Barry looks to Caitlin.

"We leave him," she says flatly.

"What?" Joe and Iris both ask.

"He's safe in there. All the other people who came out of husks were perfectly healthy. When caterpillars go into cocoons they literally break themselves down into a goo before reforming. If we open it now who knows what we'll find. Best to let it run its course."

"So, you just want me to leave my son in that thing?" Joe asks.

"Yes," Caitlin says dryly, "I do."

Iris pulls Caitlin aside while Joe's face turns an angry shade of red. Barry and Cisco stare between the two of them.

"You really think he'd be safer in there?" Iris asks her quietly.

"I don't know, Iris," Caitlin groans. "I know nothing about this thing. All I know is every other husk we've encountered has been untampered with and the people have come out fine."

"With powers," Iris reminds her.

"So? He'll be alive," Caitlin says. "And I trust logic over the gut of an overprotective dad who wants to rip that thing open."

Caitlin gives a judgmental look to Joe who is already staring at her. They rejoin the group.

"I think we should leave him," Iris says.

"You what?" Joe exclaims. "Why?"

"Because all the other metas were fine. They weren't hurt in the husks."

"They're right," Barry cuts in. "Whatever this Alchemy is up to, it's against me, not them. I don't think he's trying to hurt these people."

"You don't consider this hurting my son?" Joe asks, gesturing to the husk.

"I mean it's not ideal, but he isn't being harmed as far as we know," Caitlin says, her attention on Wally's monitors.

"Would you be saying the same thing if it was Cisco? Or is it just my son you don't care about?"

Caitlin steps up to him, her eyes venomous. "I would say the same damn thing because I'm not gonna put someone I love at risk because I let my emotions get in the way of common sense."

"Aw, you love me?" Cisco says dramatically, trying to diffuse the tension.

Caitlin and Joe hold each other's glares.

"Cisco," Caitlin says, coldly, her eyes still on Joe. She nods her head toward the doorway and walks out. Cisco follows.

"Where are you two going?" Joe calls.

"To see why that breach almost knocked him out," Caitlin calls back. She turns to look at him. "Or would you like to argue with me a little longer and keep me from helping someone else?"

He doesn't answer. Caitlin huffs and walks out.

"You had a mini stroke," Caitlin says, looking over Cisco's scans. "No more interdimensional breaching anytime soon."

"Okay, whoa!" Cisco says, sitting up quickly in the bed. "You can't just gloss over 'mini stroke'. What does that mean? Am I gonna have this headache forever?"

"It means take some aspirin and you'll be fine," Caitlin says dryly.

Barry chuckles.

"Are you alright?" Caitlin asks. "What did that thing do to you?"

"I'm not sure," Barry says. "I've never seen something move that fast. It wasn't even like we were moving; it was like we were teleporting from one place to another. Even from my perspective."

"What was it?" Cisco asks.

"Not sure," Barry says. "But at least now we know Alchemy is just the lackey. This thing is what we're really up against."

"But only you can see it," HR says, walking into the room.

"Maybe since you're both speedsters?" Cisco offers.

"Maybe, but I think he's more than a speedster," Barry says.

"What then?" Caitlin asks. "Did he say anything else?"

"He said his name was Savitar," Barry says.

"Mm, Hindu god of Motion," HR says between sips of coffee.

"What?" Cisco turns in shock. "How do you know that?"

"Crossword puzzle wizard," HR says. "On two plants, I might add."

"He said he was a god," Barry says, looking curiously at the ground.

"That's, that's nice," Cisco mumbles. "That's not scary...at all."

Caitlin walks out without a word to the others.

"Does she seem off to you?" Cisco asks.

"I think she's just nervous," Barry says. "She doesn't like not knowing things and this whole Wally-husk issue is a mystery to her." He notices Cisco's face. "Why? What else could it be?"

"She said the more she uses her powers, the more she loses control."

"Okay?"

"That's the longest she's used them," Cisco says. "What if she-"

"She's not!" Barry snaps.

"Not turning," Cisco says. "What if she upped her dose?"

"You think she took more pills when she came back?" Barry asks. "She does seem kinda-"

"Void?" Cisco says. "Yeah. It's been like talking to a robot since we got back."

Barry sighs. He hoped it wouldn't come to this. He doesn't want to have this conversation with her because he doesn't know what alternative to offer. What else can they do?

When they get back to the cortex Joe is hovering behind Caitlin who is checking something on her computer.

"What are you looking for?" Joe asks.

"I don't know."

"Of course, you don't," Joe groans. "You don't know anything about what's going on here." He storms out of the cortex.

Caitlin moves her hands from her computer, tenses them and pushes clenched fists into the desk. Barry walks up next to her and places his hand on hers. He can feel how cold it is. Beyond what is normal for a typical human.

"Can we talk?" He asks.

Caitlin turns to him and smiles. She walks to the back of her lab with him.

"What's up?" She asks, her voice lighter.

"Are you okay?" He asks. "I know how much that took for you to use your powers, but you saved my life. Thank you."

Caitlin raises up to kiss him. "You've saved me plenty, Bar. I owed you."

Barry chuckles nervously. "Uh, Cait you've seemed off...since we got back. Cisco thinks...well we both think...did you take more when you got back?"

Caitlin gives him a reassuring smile. "No, Bar. I'm sorry I was off earlier. I was just frustrated with the whole Wally and Joe thing. Look, I know we talked about it before but I...I feel better. I was worried about losing control but I think the more I use them the more control I have. I think suppressing it was making it worse."

Caitlin walks over to a drawer and opens it, taking out six bottles of pills. She pours them out in the sink and washes them down.

"No more numbing," she says, smiling at Barry.

Barry hugs her from behind, burying his head in her neck. "Are you sure"

"It can't be about me, Barry. There's so much going on that if I focus too much on how I'm feeling then I'll just get stuck in it. No more looking back. Just forward." She sinks back into him. "I'm gonna go talk to Joe."

"Haven't you two fought enough this morning?" Barry sighs.

She turns, still smiling at him. "I want to apologize."

"He owes you one too, y'know," Barry says.

Caitlin shrugs, "then I'll take the first step."

***

Caitlin knocks on the door to the interrogation room where she was told Joe was with the acolyte they arrested from the subway. Joe answers.

"What is it? I'm busy," he says.

"We decided to cut Wally out," she says with a smile. "We thought you'd want to do it. You'd be the most careful, after all."

"What?" Joe asks, his face filling with relief. "Of course."

Caitlin steps back to let him through. Joe looks back hesitantly at the man in the room before running out. Caitlin places her foot into the doorway. She slides in when Joe is out of sight and locks the door. Caitlin stays facing the door. She looks at the camera out of the corner of her eye. Before stepping into its view, she raises her hand and covers it in ice. When Caitlin turns to face the acolyte her hair is lighter, streaked with white and blending into her pale skin. Her eyes are glowing blue. She slams her hand down on the metal table, coating it in ice. The acolyte jumps back.

"Where is Alchemy?" She asks darkly. Her voice airy and cold.

"I sense great fear in you," the acolyte says, having regained his composure. "You fear your power. Your own greatness."

"Where is Alchemy?" She repeats, more insistent this time.

"I don't fear you," he spits. "The only one I fear is the one whom Alchemy serves: the dark lord, Savitar."

A smirk spreads on Caitlin's face. She grabs his cuffed arm. Ice spreads up his arm, piercing and numbing every inch of his skin.

"How cold does skin need to be to shatter, do you think?" She taunts. "Shall we test it out?"

Caitlin squeezes his arm tighter and the ice begins to crack. He screams in fear and pain. The light in her eyes glows brighter. More strands of her hair whiten.

Banging on the door draws her attention away. She looks back at the man who is gripping his arm in agony. He was not going to give her what she needed. The banging on the door continues. Caitlin blows a thick frost out of her mouth, filling the room with frozen mist that fogs the visibility. The door flies open and two officers walk in, blinded by the fog. When they step inside, Caitlin steps around them and leaves without being seen.

She freezes the door handle to postpone them and walks swiftly down the hall.

"Hey!"

Caitlin freezes. Julian is behind her. He can see the frozen door handle, and she is the only other one in the hall.

"What are you doing here?" Julian asks.

Caitlin takes a deep breath. She can feel the glow fade from her eyes. She turns to him.

"I was looking for Joe," she says.

"Why? What's going on in there?"

"No idea," Caitlin shrugs. "He asked me to do a psych eval on the man they captured last night. While I was in there the room just filled with fog."

Julian looks back at the room. "What did you discover from the evaluation?"

"He honestly believes he's serving some messenger of a god," she says. "This Alchemy."

Julian just sighs. "Another idiot spouting off stuff about Alchemy."

"I was just going to find Barry to have him do a search for anymore followers. See what they can tell us."

"I can help with that," Julian says. "Allen hasn't come in yet today."

Caitlin just smiles. "Perfect.

***

"Alright, how do we want to do this?" Joe asks excitedly, walking into the cortex.

"Do what?" Cisco asks.

"Cut open the husk."

"We all agreed not to," Barry reminds him.

"Caitlin just told me you decided to cut him out," Joe tells them. "Said you all figured I'd want to be the one to do it."

"We never said that," Cisco says, turning to Barry.

"Cait said she was coming to the precinct to apologize," Barry tells him.

Joe turns to him, confused.

Barry's face falls, panic clear on it. Cisco's matches.

"Sounds like our doctor has been weaving quite the web," HR says, gesturing with his drumsticks.

Barry runs out of the cortex. When he arrives to CCPD he sees the acolyte they arrested leaving in a gurney.

"Idiot," one of the cops says, "about froze his own hand off."

"Hey!" Barry calls to him. "What happened?"

"We heard the guy scream. The whole room felt like a freezer. He about froze his entire arm off. These metas, I swear, they're all crazy."

"He did this to himself?" Barry asks cautiously, hoping they've bought that story.

"No one else was in there. The cameras were frozen but there was no sign of anyone else in there with him before the cameras cut off so it had to be him. Probably trying to escape."

Barry just nods. He looks around for any sign of Caitlin. He doesn't want to be too obvious. He walks up to his lab to try to call her. She's sitting across from Julian's desk. Her hair is whiter than when he saw her this morning.

"Cait," he mutters in relief.

She smiles at him. He motions for her to talk to him away from Julian.

"What happened? With the acolyte?" He asks. "And Joe, he said you told him to cut the husk."

"I told him he could," Caitlin says flatly. "I thought about apologizing, but I didn't really owe him one. I told him how I felt about it, so if he still wants to cut it open, that's his call. It's not on me."

Barry stares in shock at her. "Cait, the acolyte, he-"

"Had powers," she says, "turns out. I went to do a psych evaluation on him and the room just started fogging up."

"And his arm?" Barry asks.

Caitlin shrugs. "I didn't see anything happen to his arm. I couldn't see anything once it fogged up. I got out of there as quick as I could."

Barry is still staring in concern at her. "What are you doing now?"

"Julian is making an algorithm to find Alchemy's followers," Caitlin says. "We're looking for anyone who has searched a key word in the last six months."

"Why'd you ask Julian?" Barry asks.

"He was here."

"I'm done," Julian announces. "What keyword? Alchemy is relatively common."

"Don't look up Alchemy," Caitlin says.

"What shall I look up then?"

"Savitar."

Julian turns to her and there is a hint of knowing in his face. That word means something to him. Caitlin nor Barry bother to question it.

"We can't just go question them without reason," Julian says.

"You can't," Caitlin points out. "But I can."

Caitlin walks over to stand next to Julian. Two names appear on the screen with addresses next to them. Caitlin grins. She starts to walk out.

"Where are you going?" Barry asks, following her out into the hall.

"To talk to Alchemy's followers," she says dryly.

"About what?"

"Where he is. Who he is. What the husk is," Caitlin lists. "I don't like being in the dark, Barry."

"I'm coming with you."

"No, you're not," she says. "You're part of CCPD and you questioning them could get you in trouble."

"And what makes you think they'll talk to you?" He asks.

Caitlin shrugs. "I'm more charming than you," she says with a smile, continuing to walk away.

"Cait!" Barry calls. She turns. "You're scaring me."

Caitlin walks up to him, her eyes warm. She grabs his hands and holds them between hers, squeezing them reassuringly.

"I'm doing this for us," she says. "Everything will be okay."

She walks off. He knows he can't chase her. He can't do anything. She's not acting like herself, but he doesn't know what it is. He can't do anything until she does, and he won't accuse her of anything until then either. He just has to trust she knows what she's doing. He runs back to his lab, checks the addresses she got from Julian, and runs out before he notices.

"Cisco!" He calls when he gets back to the cortex. "How do you feel about a stake out?"

Cisco and Barry each take a house. They watch and wait for Caitlin to arrive to one. They aren't going to confront her, but they want to be there in case things go wrong. Cisco agreed with Barry that she'd been acting weird, and neither of them were buying the story of the acolyte freezing his own arm.

They wait for hours. She doesn't show up. Seemingly ordinary people arrive home from work and don't leave the rest of the evening. It gets dark.

Caitlin sees the S.T.A.R. Labs van sitting outside the acolyte's house. She enters through the backdoor. Caitlin sits in the living room and feels the cold air radiating off her body. She waits. After a few minutes she hears stairs creaking. A man appears around the corner and checks his thermostat.

"Bit chilly, dontcha think?" She says softly.

The man jumps. "Who are you?"

"Irrelevant," she says.

She stands and faces him. She walks slowly around the couch until she's standing just in front of him.

"Who is Alchemy?" she asks.

"I don't know what you're talking about."

Caitlin smirks. The man starts to cough and grab at his throat. He gasps, panic filling his eyes. He suddenly inhales, leaning over and breathing deeply.

"Let's try this again," she whispers sharply. "Who is Alchemy?"

"I don't know," he pants. "I've never seen him without the mask."

"He's restoring versions of people from another timeline," Caitlin says. "How?"

"I don't know," he admits, "but it's not him. Alchemy is just an acolyte, like me. We both serve the speed god, Savitar. He's the one who picks the chosen. He restores them. You can't make him doing anything."

"I can be quite compelling," Caitlin says.

The man smirks, the panic having slightly faded from his eyes. "He's shown us the future. I saw you there, Caitlin Snow."

Caitlin clenches her jaw and fists. Her eyes illuminate the room.

"He will restore nothing for you. You are becoming exactly what he needs you to be. He has special plans for you...Killer Frost."

Caitlin inhales sharply, stepping back from the man. She looks around and realizes she's covered the entire room in a sheet of ice. The man is staring in awe at her. A flash of blue in her periphery catches her attention. Her breathing picks up and the ice fills her veins.

"Caitlin!"

Cisco's voice calls from outside. Caitlin takes one final look at the man in front of her. He swallows, scared. Caitlin sighs and walks outside. It's raining. The lawn outside the acolyte's house is frozen.

"Aw look," Caitlin taunts, walking to stand in front of Cisco on the street. "You brought your toys."

Cisco takes off his goggles. "I'm hoping it won't come to that.

"You always are," she bites.

"I want to help you, Caitlin," he says gently.

"Of course, you do. That's all you two ever want to do is help. You say it an awful lot for two people who never actually do it."

"Just tell me what to do."

"I've told you what to do!" She spits. "But you're too weak to do it."

Cisco just stares at her.

"You or me, Cisco," Caitlin says.

Caitlin raises her hand, her palm facing him. A dark grin grows across her face. A single icicle shoots out of her hand at his feet. He jumps. Her grin grows. A flurry of icicles emerge from her hand. Cisco runs behind a nearby tree.

"Caitlin, please!"

"Please what, Cisco?" Caitlin calls back. "You want to help? Show me you can. What are you willing to do to help me?"

Caitlin freezes the tree he's hiding behind. Cisco puts on his goggles and steps out, aiming a blast at her. She dodges it easily.

Yellow lightning appears down the street. She freezes the road. The lightning disappears and Barry, in his Flash suit, slides uncontrollably down the road. He rolls to a stop and grunts in pain. Caitlin walks slowly toward him.

"How about you, Bar?" She taunts. "What are you willing to do?

"Cait, please," he begs.

Caitlin stands over him, looking down.

"Please, what?"

"Listen to us," he says. "You don't need Alchemy."

Caitlin chuckles, dropping down to her knees, straddling him.

"I don't?" She taunts. "Prove it. Stop me."

Caitlin leans down and kisses Barry. His lips turn cold against hers. She hears him struggling under her, gasping as his face and breath freezes.

A blast from Cisco sends Caitlin flying off of Barry. She lands hard on a nearby car and rolls off. She gets to her feet, an amused grin on her face.

"Start vibrating," Cisco tells Barry, "it'll warm you up."

Caitlin and Cisco circle each other around Barry.

"Your move, Caitlin," Cisco says.

Caitlin twitches her hand and he flinches. She smiles.

"You sure you're ready?"

They continue circling each other. Cisco starts flinching more as the rain hits him. Frozen, sharp droplets cut into his skin. They grow. The rain around Cisco turns to hail the size of golf balls and start pelting him. Cisco struggles to get out of it, but it follows him. The hail circles around him until he's enclosed in a hollow cylinder of ice.

Caitlin stalks toward Barry again. He's warming up. She leans over him.

"You can't do it," she says disappointedly, "either of you."

Caitlin drops to her knees, her hand gently on Barry's cheek. The glow of her eyes dim. The warm brown reappears.

"He's restoring parts of Flashpoint. You said my powers didn't change me there," Caitlin says.

Barry looks pityingly at her. She flinches back, her eyes glowing blue. An ear-splitting crack sound scares her. She turns to see the ice cylinder around Cisco shatter. She turns back to Barry, fear in her eyes.

"Don't come after me," she begs. "You won't love me like this."

An icicle forms in her hand. She stabs the side of his calf and Barry yells out in pain. Caitlin is thrown away from him by Cisco again, this time hitting her head hard on a nearby light pole. She lay unconscious on the ground. Cisco runs up to Barry .

"Are you alright?"

"I can't run," Barry gasps, holding his bleeding leg.

Cisco helps Barry into the van and lifts Caitlin into the back. They drive back and without speaking to each other, they both know what they have to do. Barry limps alongside Cisco. They carry Caitlin down to the pipeline. They lay her in a cell and close the door.