A/N: This is a possibility for understanding Killer Frost's origins, built on the repressed memory Caitlin recovered in 4x22. Let me know what you think!

"There was a robbery at a pawn shop that just opened."

"I'm on it," Barry said, getting into his suit.

"It's already over," Cisco said. "It happened a few hours ago, apparently."

"Why are we just hearing about it now?"

"New place, not in our system yet," Cisco said quickly. "CCPD just found out too. But there's something weird. The report says the witness… is an eight-year-old."

"What's so weird about that?" Caitlin asked.

Cisco held out his tablet for them to see. "She was thirty yesterday." The tablet showed a smiling woman holding up an old-fashioned pocket watch to advertise the store – which was hers, from the looks of it.

"So our thief is a meta who can de-age people?" Barry asked. "Is that possible?"

"You should know by now, Barry," Caitlin said with a slight smile, "nothing's impossible anymore."

"Right. Okay, then let's make a plan. We don't want to be turned into kids when we find this guy. I'll go talk to the witness with Joe."

"We'll work on something," Cisco said.

"If you can get a sample from the witness for me?" Caitlin asked.

Barry nodded and left.

"Even for us, this one's a little weird," Cisco said.

"Yeah," Caitlin replied absently, staring into space. She was already trying to figure it out. Was the change purely physical, or mental as well? It had to be reversible. Would there be any adverse effects once it was reversed? She wouldn't know until Barry got back with that sample, and told her how the interview had gone. She hoped it was sooner rather than later.

Barry didn't disappoint. It was a little over an hour later that he appeared back in the lab, Ralph in tow. He handed Caitlin a DNA sample, and she started setting it up as he explained what had happened.

"The woman, Chance, looks eight or nine at most, but acts like an adult. The meta just touched her, and she changed."

"Her mental faculties weren't impaired?" Caitlin asked.

Ralph scoffed. "She seemed pretty 'there' to me. Practically threw me out for touching a jewelry box."

"He almost dropped it," Barry supplied.

"Any clues about the Pacifier's identity, or another target?" Cisco asked.

Caitlin smiled as she started analyzing the DNA. It wasn't a bad name. Cisco had come up with it a few minutes after Barry had left. They kept talking as she entered a hyper-focused state, fully in scientist mode. She was thorough, but there wasn't much she could tell aside from the obvious: "she's younger," she said once she was done.

"I don't want to be a Ralphie downer, but didn't we already know that?"

"Yes," Caitlin said. She swiveled around to face them. "There doesn't seem to be any damage to the DNA, which is good. Otherwise, this doesn't tell me much."

"If you had a sample from the…"

"Pacifier," Cisco said.

"Pacifier," Barry said, "could you find a way to reverse it? I don't think that woman wants to look like a kid forever."

"I'm sure," Caitlin said. She didn't know how to reverse it yet, but it shouldn't be that hard. She'd have to take her time making the cure. Barry could probably do it, if something did go wrong…

"Caitlin, you alright?"

Caitlin blinked and came back to herself. Cisco was right next to her, his eyebrows pressed together. "You've been spacey all morning. You feel okay?"

"Yeah, of course," she said, standing up. "Just trying to figure this out."

"We all are," Barry said. "But since there's nothing we can do right now, do we want to -."

The alarm in the cortex went off, and Barry sighed. "Or not."

They ran to the cortex, and Cisco leaned over the monitor. "Pacifier strikes again. A jewelry store this time."

"How long ago?" Barry asked.

"Right now!"

Barry raced into his suit, but Caitlin instinctively called for him to wait even as he did. She ran to her desk and grabbed the cold gun, and ran back to the cortex, her heart starting to beat faster in anticipation. "I'm coming too."

"Caitlin, we don't have time to -."

"I need to be there, to help anyone he's whammied."

It wasn't the strongest excuse, but something in her expression must have told Barry she wouldn't take no for an answer. He reluctantly nodded and picked her up, racing them to the robbery in progress. Barry set her down as the meta turned to them, setting down the gold necklace in his grip.

"You made a mistake," the meta said.

"What's that?" Barry asked, stepping forward. Caitlin held her cold gun up loosely, to look as though she planned to use it. Just a little closer.

"Forgetting a babysitter."

"Get down!" Barry cried as the meta lunged forward. Barry moved to cover Caitlin, one arm stretched back while the other set up a barrier for the meta, starting to rotate and make a wind funnel.

Caitlin rushed under Barry's protective stance and pushed her friend with all her might, shoving him out of the way and effectively ending his defense. In the next few seconds the meta grinned; Barry's mouth opened and framed her name; the meta's hand clamped onto her shoulder, and Caitlin almost smiled.

"Why would she do that?" Barry asked. "Why would she push me out of the way?"

"Maybe she thought it was the only way to protect you," Cisco said.

Caitlin opened her eyes and squinted at the brightness of the lab. Cisco and Barry were right next to the bed she was laying on.

"Hey," Barry said, casting a relieved smile at her. "How are you feeling?"

"Fine."

Caitlin inhaled sharply. Her voice was higher than normal. She looked at herself and had to fight to contain her smile. Her feet didn't reach the end of the bed. Her hands were small.

She put a hand to her forehead and felt the bangs she'd had at that age. "It worked," she said.

"Unfortunately," Cisco said. "And Pacifier got away."

I'm sorry," Barry said. "I knew he didn't really hurt you, but when you collapsed… I just wanted to make sure you were safe. I'll get him next time," he promised, "and we'll get you back to normal." He put a hand on her leg reassuringly, and then seemed to realize it was awkward and removed it.

"Are there any other metas we can go after in the meantime?" Caitlin asked. The Pacifier wasn't even a concern at the moment.

"You seem oddly eager for action," Cisco said, narrowing his eyes. "And you're not going anywhere like this."

Caitlin jumped off the bed. "Yes, I am." She tried to stare him down, but having to look up at him took most of the intimidation out of the stare she'd mastered as an adult. "I'm going to check for any signs of trouble in the city."

"Cait, why do you want to find another meta?" Barry asked, following her.

"Because," she said, looking determinedly ahead. "that's how I'm going to get Killer Frost back."