Author's Notes: I can't wait to see how canon eventually wrecks this fic, but, whatever. This is for fun.

Quick warning about this fanfic: it's going to be redundant in some parts. Because of how "Flash Back" left canon almost entirely untouched, there's simply not a lot that can be changed. But I hope that what I do change, the way the characters interact, how Hartley shifts things around him, I hope that is entertaining.

Please enjoy!

"Well," Hartley said, sounding amused from where he was leaning against the back of his cell, "this is familiar."

Cisco frowned at him. It was familiar: Hartley standing in the cell, pale as a ghost, blue eyes watching behind square-rimmed glasses, brown hair douchily tousled, the glass door between them un-cracked, Cisco holding Hartley's inventions in his hands. The main difference was time, the urgency of the moment because he knew he had a limit of it. Cisco's tan hands tightened around Hartley's fried sonic gloves.

"We got interrupted before," Cisco said.

Hartley scoffed. "Are we expecting the dementor to be back, too?"

There was a big part of Cisco that was thankful to Hartley for probably saving his life, and that part wanted to squawk at him, tell him, "Yo, me too! I said that too!" The other part, however, remembered what Doctor Wells said, that it was probably simple self-preservation that made Hartley act to save Cisco, Caitlin, and himself. That kept Cisco's reaction to just the slightest of lip-twitches, brushing a stray strand of black hair behind his ear.

"No," Cisco said firmly. Then he paused. "At least, not yet?" Hartley just looked unimpressed, and Cisco couldn't help himself. "It's a future problem."

'Cisco, no,' a voice that sounded like a combination of Doctor Wells and Caitlin hissed in his mind.

At Hartley's continued bland stare, Cisco shook himself free of that thought and held the gloves up. "It's actually partly why I'm here. Your gloves got wrecked when you used them against the dementor, and the destructive signal you used is the only lead we have on destroying that thing. And we need to know how to destroy it."

Hartley perked up at that. "'Need'?" he echoed.

Cisco scoffed. "Slow your roll, cowboy. The timeframe's about a year. We could do it without you." Maybe. If they had two years, definitely.

Hartley's head tilted, just slightly, to the side. The light glinted eerily off his glasses, and Cisco knew he was doing it on purpose. "Then why don't you?" he drawled. "Why ask me for help at all?"

Cisco glanced to either side, raising his eyebrows. "Be-cause you're the expert on these things and you can do it faster? That's generally why people ask other people to join in on a project." Cisco held up his hands, waving the gloves a little. "I know, I know," he continued, mockingly, "you've never had to work with another person on a project in your life－"

"And the other things?" Hartley grumbled. He'd crossed his arms during Cisco's little speech. "If the gloves are only partly why you're here, what else is there?"

And Cisco's throat tightened, and his mouth hung open uselessly. Hartley stared at him, eyebrows raised. "I－You－" Cisco tried, sounding strangled. He stopped, clenching his jaw, and swallowed.

Hartley stepped forward in his cell, head turning slightly to the side in his curiosity, like a bird. "Cisco?" he asked, a little tentative.

"You know how to find Ronnie," Cisco finally blurted.

Hartley stared in stunned silence.

Cisco scrambled forward, setting the gloves on the ground. "Look, listen," he started, "Ronnie... Ronnie's in trouble. He's not well, Hartley, he's... God, man, he looks like he hasn't slept under a roof since the explosion."

Hartley was still just staring, and Cisco pressed his hands against the glass cell door. "I'm begging you, man. You have to help."

"How did you know that?" Hartley finally asked, voice almost a whisper. His eyes were wide, and he moved closer to the glass, to where Cisco was standing. "You want my help? Tell me how you knew that."

The esteemed Doctor Snow-Wells was shouting warnings in Cisco's head again.

Cisco looked to the ceiling, grimacing. "I am going to get into so much trouble for this," he muttered. Hartley's eyes narrowed in confusion, and Cisco sighed. "Alright, dude. Time travel. That's how I know."

Hartley blinked.

Cisco nervously continued, babbling again, "We know the dementor-thing won't be back because it's currently going to... or already is a year or so in the future. And I know you know because... someone from the future told me."

Hartley was just staring again. Cisco groaned.

"C'mon, man," he grumbled. "Either believe me or call me a liar. It's the only story I have."

"The Flash," Hartley whispered, almost too quiet for Cisco to hear. He moved away from the glass door, staring into space. "The Flash can go fast enough to... to break through the space-time continuum?"

Cisco shrugged, and the movement drew Hartley's attention again. "Eventually, anyways. Not yet. I think." He shook his head. "Time travel is very confusing, and we've only known it was possible for, like, less than a day."

Hartley tried to pace across his cell, but it was too small for that. He glared at his left wall, hands clenching and unclenching, before he turned back to Cisco. "You want my help? With the dementor, and with Ronnie?" Cisco nodded, and Hartley, like a whip, slammed a palm against the wall. "Then get me out of this thing."

Cisco's mouth opened, shut, and then he cringed. "Hartley. You attacked Doctor Wells. You blew up police cars." He paused, and spread his hands. "You also broke some windows on your parents' building, but they totally deserved that."

A small flicker of a smile appeared on Hartley's face, but it was chased away by his seriousness. "I'm not asking you to set me free," he snapped. "I wouldn't say no, but, that's not what I'm asking." Hartley pressed his palms against the glass door. "If you want my help, then let me help."

Cisco hesitated. He'd had a daymare about get caught up in one of Hartley's ear-bombs earlier. It had been vivid and terrifying, flying through the air, and he could almost feel the pain. Caitlin had recommended he get some sleep, but then she always did. "I'll have to convince the others," he finally said, but Cisco was sure he could manage it. Hartley had saved Caitlin and his lives. It had to be worth something. It had to be.

Hartley smirked. "You'll get it done," he said with an air of finality. Then he let out a small laugh. "And, I guess the whole 'Future-Flash' does explain something."

Cisco raised an eyebrow as he walked over to gather the sonic gloves. "Oh? Like what?"

Hartley held up his hands, slowly wriggling his fingers. "When the Flash grabbed me, outside Rathaway Industries, he told me, 'Got you again.'" Hartley rolled his eyes, dropping his hands to his sides. "I was worried that I might've dated him at one point. This? Is far less creepy."

Cisco blinked rapidly. "That says something about the guys you've dated that that was even a possibility."

Hartley smirked. "I suppose I should've jumped to 'time-traveler from the future'?"

Cisco paused, mouth open, and then huffed. "Fair enough." There was an awkward pause, where Cisco held the sonic gloves, and Hartley stared at him. Finally, Cisco frowned. "You're still a dick."

That startled a bark of laughter out of Hartley, who then smirked. "But at least I'm working with you."

"Small mercies," Cisco muttered, walking to the control console. He paused beside it, hand hovering over the controls. He looked at Hartley, and nodded to him. "See you soon, Hartley."

Hartley nodded, a twist to his lips. "Adiós, Cisquito."

Cisco rolled his eyes, and then sealed Hartley away.

Turned out that simply stating again that Hartley had saved Caitlin's and Cisco's lives wasn't enough to sway Doctor Wells.

"What part of 'he stays in his cell' is hard to understand?" Doctor Wells grouched. He was sitting in the middle of the laboratory, arms crossed, blue eyes narrow behind his half-rim glasses. Barry was standing to his right, and his arms were also crossed.

They looked oddly like father and son, both brunets with grumpy expressions. If Cisco hadn't been so frustrated, he would've thought it was funny.

"He's dangerous," Barry said. His green eyes grew wide and he shifted to spread his hands out. "The guy put bombs in his ears."

Caitlin, who was standing beside Cisco and opposite Doctor Wells and Barry, frowned. "We're not suggesting we just give him free reign of the lab equipment," she said, a touch tart. She shook her head, brown hair bouncing. "But we don't know how long it's going to take to repair the gloves, or what frequency we need to use, or how to adjust the frequency, or how to weaponize sound waves like he did, or－"

"I understand that, Doctor Snow," Doctor Wells said, dryly, and Caitlin fell quiet. "That doesn't change the facts: likely the only reason he wants into the lab is to facilitate his escape. We cannot risk having a brilliant mind like his poking around our computers."

"That's an easy fix," Cisco chirped, raising his eyebrows when Doctor Wells frowned at him. "We just have to make a transmitter that gives off a signal to deny access to our files. Then we attach it to Hartley."

"Easy, huh?" Barry grumbled.

Cisco raised an eyebrow. "Ye of little faith."

Barry, unconvinced, crossed his arms again. "And if he decides to try and use his gloves on you?"

"Seriously, I have a plan," Cisco said. "There's some blueprints for handcuffs we were working on for the police before..." Cisco waved his hand through the air, "but it fell through because it gave the inmates too much range of motion."

Caitlin bit her lip. "Hartley isn't a bad person," she said, quietly. "He's a real jerk, don't get me wrong," she added when Cisco shot her a look, "but that doesn't mean he's evil."

Barry gestured to Doctor Wells, who was looking intently at Cisco. "He attacked Doctor Wells," Barry said. "In his home."

Cisco cringed. "Yeah, I know, but－"

"There's something else," Doctor Wells said, suddenly, and Cisco's hands snapped to his chest, curled into fists. Doctor Wells's eyes narrowed. "You're wildly intelligent, Mister Ramon, you know you could eventually figure out the gloves, the frequency variance."

"Not in time," Cisco muttered, futilely.

"But that's not what's driving you," Doctor Wells said, and he tilted his head, just a little. "What is it, Cisco? What else does he have?"

Cisco glanced from Barry to Caitlin, pressing his knuckles together. "Ah, well," he started. Failed. Then, with a deep breath, he closed his eyes and said, "He knows where Ronnie is."

The silence was deafening.

"He what?" Caitlin asked, clipped and hard.

Cisco opened his eyes and found himself now facing down three people alone. Caitlin's brown eyes stared hard at him, and Cisco shook his head. "I know, I know, it sounds like a trick, but it's not. I promise you guys it's not."

"Cisco, I told you," Caitlin began, and Cisco shook his head harder.

"It's not－it's not just for you," he said, quietly. His heart was racing, and his eyes felt hot. "It's for me. Because... because of what I did."

Caitlin blinked, drawing back. Barry's brow furrowed. Doctor Wells steepled his fingers, elbows resting on his legs. "What are you talking about, Cisco?" Doctor Wells asked, gently.

Cisco swallowed heavily, but he couldn't fight the tears as they rolled down his cheeks. "I-I sealed Ronnie into the particle accelerator. Before it exploded."

Caitlin's face, eyes going wide and cheeks going pale, broke Cisco's heart. He continued, tearing off the bandage. "He told me to wait two minutes, and I did but..." Cisco wiped his cheeks with his sleeve. "He didn't come back. And I just... I keep thinking. If I'd waited ten seconds. Twenty seconds. Maybe... maybe Ronnie wouldn't be like he is now."

Caitlin swallowed. "Cisco."

"I'm so sorry," Cisco said, through gritted teeth. "I wanted to tell you, so many times before but I－"

"Cisco, it's okay," Caitlin said, and swiftly latched onto him, pulling him into a hug. Cisco could feel the slight quivering in her hands. "What happened wasn't your fault. It wasn't anybody's fault."

Cisco grabbed the back of her shirt and just hung on. Just for a moment.

"Ronnie would tell you, that you did the right thing," Caitlin murmured. "Thank you for telling me."

There was a long sigh, and Cisco pulled his head away from Caitlin's shoulder to blink at Doctor Wells. His eyes were closed, his hands resting in his lap. "I suppose you should dig out those blueprints, Mister Ramon," he said, opening his eyes. "Let's see if we can add a transmitter to them."

Barry tilted his head slightly to the side. His own eyes were glassy, but he looked curious. "But, how do you know you can trust Hartley to tell the truth?"

Cisco shrugged, stepping away from Caitlin and grinning. "Easy," he said, voice only a little rough. "I was told to by a most trustworthy source." He smiled. "You."

Barry blinked, and then let out a small laugh, even as his cheeks pinked. "I'll remember that the next time you accuse me of cheating at Mario Kart."

Doctor Wells backed up, nodding down the hall. "Do you think you can get started without me? I'll be back in a moment."

Cisco nodded, smiling. "Not a problem, Doctor Wells. We've got this," he said, and bound over to his workstation. Barry and Caitlin were only a few steps behind.

"I've got to see these handcuffs," Barry muttered.

Cisco grinned. "They're magnetic."

Hartley wasn't surprised when he felt his cell lurch into motion again. He had heard the small motor coming down the hallway several seconds ago, could hear the sound of tires rolling over to the console by the pipeline door. The anti-proton cavity－repurposed as a prison cell－he was being kept in was hoisted by the maintenance arm, its mechanics grinding loudly in Hartley's ears.

But above it all, Hartley could still hear the slightly-fast heartbeat of Harrison Wells.

The moving stopped. Hartley rolled his shoulders against the wall, and then shoved himself to his feet, straightening his shirt and pants. He'd been waiting for this almost since he first arrived, sniping at Cisco and Caitlin, and flirting with the Flash. He was, however, a little surprised at how quickly after Cisco had left that the man had chosen to come talk to him.

Another beep, and then more pistons moving as the large metal doors leading to the lab proper opened. And there, alone, sat Harrison Wells. The game was on.

Hartley opened his mouth.

"I don't have time for a tête-à-tête, Hartley, so I'll make this quick," Wells said, and Hartley stilled. This was not the Wells he'd played chess with. No, this was the Wells who'd blackmailed him into allowing countless people to be injured. Into allowing seventeen people to die.

Hartley's heartbeat quickened. "I take it this means none of your little pets are watching," he said, mind racing. Every instinct in Hartley was screaming DANGER DANGER DANGER.

Wells smirked at him, and then said, voice low and dark, "You're not going to breathe a word of my secrets to anyone."

The certainty Wells spoke with was horrifying. Hartley couldn't help his small, startled intake of air. It was probably unnoticeable to Wells, but Hartley could hear the sharp hiss of the gasp, the ratcheting of his own pulse.

This was not the man who had blackmailed him. This was another mask－or maybe the others were masks, and here, finally, was the true face of Harrison Wells.

Hartley wished he'd never seen it.

"And if I don't?" Hartley asked, barely able to keep his tone level. Because he had to know the stakes to this game. What the rules were, what the punishments were, what the win condition was.

When he would have to flip the board over.

Wells leaned forward in his wheelchair, eyes narrow behind his glasses. "Then," he hissed, "I'll do worse than leaving you in this cell, alone, for months. I'll do worse than Rickroll you. I'll do worse than blackmail you." He leaned back. "Do you understand?"

Hartley's heartbeat pounded. He kept his expression blank. "Completely," he said, and felt a small quiver start in his fingers.

Wells smiled. "Good," he said, starting to turn around. "Then, I guess I'll see you soon, Hartley."

"Do they know?"

Wells paused, turning slightly in his chair. "Know what?"

Hartley swallowed, throat dry. "Do they know that you don't need that chair?"

Wells watched him for a moment more, and Hartley did not squirm. "If that rumor starts spreading," Wells murmured, probably barely loud enough for the man's own ears, but Hartley's picked them up perfectly, "then you'll be the one in need of this chair."

Wells didn't wait a second more before slamming the metal doors closed. Hartley kept himself still, blank, as the cell moved back into its slot on the wall. There were cameras, Hartley was sure, and he wasn't going to give Wells the satisfaction of his fear. When the grinding stopped, when Wells's heartbeat and whining motor moved away, finally, Hartley slowly moved to the corner of his cell and sat there, curling over his knees. His heartbeat calmed.

"A fronte praceipitium a tergo lupi," Hartley muttered, hands curling into fists, and waited.

Translations:

A fronte praceipitium a tergo lupi
- Latin; A precipice in front, wolves behind.
Essentially, "between a rock and a hard place", but Eobard is far more like a wolf than a rock. Said by Hartley to Eobard in the flashback of 'The Sound and the Fury', it seemed appropriate to use it again here.