Melanie flipped through the pages of files that had been collecting dust on her desk, letting out a frustrated sigh. Even with Harvey playing CSI, he didn't even bother with the paper work.

"Son of a bitch." She grumbled, pulling out her phone and scrolled through her contacts. She tapped on Barry's name, leaning back in her chair. It creaked loudly and caused Melanie to sit up straight in fear it would snap back. Her phone began to ring.

After just a few seconds, there was a loud woosh and a blinding red light. Papers flew everywhere and Melanie did her best to catch as many as she could. She failed miserably, slapping her hands on her desk to try and stop anymore papers from flying away.

Barry stood in front of Melanie's desk and slowly, her eyes widened. Sure, she had the feeling Barry Allen was the Flash, but she wasn't 100 percent certain.

"Holy shit I was right." She mumbled, standing up quickly. Barry's mouth dropped open as he slowly looked around Melanie's lab, jealousy written all over his face.

"This place is huge! You have the entire south wing?!" Barry asked as he spun around to face Melanie for a moment before walking over to a shelf of files.

"Yes and I've only had it for less than forty-eight hours so if we could not—" Melanie rushed over to Barry and slapped his hands away from the boxes. He hissed in pain. "—touch the four decades worth of case files that probably went cold."

"Sorry." Barry pressed his lips together awkwardly, looking over to Melanie's desk. "Wow, that's more paperwork than what you left me with when you went to England."

"Well, I do live in Gotham. And this place isn't as lively and bright as Central City. Which also reminds me, you're now going to be my coffee runner." Melanie gave Barry a quick smile as his look dropped into confusion.

"What?" He mumbled and Melanie gestured towards the window.

"I've been to the Jitters down the street four times in the last two days I've lived here, and nothing in there is good. Except for the blueberry muffin. And their Robin frappe."

"They have a frappuccino named after a vigilante?" Barry frowned as he walked over to Melaniems desk. She followed after him, leaning against it and slid a paper away.

"They named a coffee after you. Which, by the way, was my favorite coffee from CC Jitters, so I expect it to be the most frequent coffee you get me." Barry scoffed quietly and picked up a file, flipping it open. "And I take my coffee black with a lot of espresso."

"How do you sleep?" Barry questioned, turning to Melanie.

"I don't. When did you ever see me outside of the Precinct?" Barry looked away to think before he frowned.

"You went to Iris' and Cora's birthday party last year. Both of them miss you, by the way." Melanie hummed in contempt before pushing herself off the desk and walked around, sitting back in her chair. It squeaked loudly again.

"Look. I know that using people to my advantage isn't a good thing. But I will literally be here until I retire if I don't have your help with doing the paperwork on all of these cases." Melanie looked up at Barry with pleading eyes, and he raised his brows at her.

"Melanie Nyx asking me for help? Well, I never thought I'd live to see the day." Barry gave her a toothy grin and Phoebe rolled her eyes.

"Yeah, well, I didn't think I'd get to tell my kids I was friends with the Flash. Help me out here and I'll show you the Bat Signal." Barry's eyes blurted out from their sockets and he grinned even harder than before.

"Wait, seriously? You have access to the Bat Signal?!" He questioned loudly and Melanie put a finger to her lips.

"Shut it! I don't think Gordon is aware that I do. There's two roof top entries and I have one of them, so I can use it to my advantage. I don't want to lose it." Barry nodded quickly in understanding before walking around to stand next to Melanie.

"Okay. I really appreciate this Barry. I think we should start with—" Melanie was immediately cut off with Barry picking up every paper that had flown around the room at lightning speed, returning to her desk. A pen went missing from her mug as Barry's arm blurred with how fast they moved. Her eyes widened in surprise as file after file was stacked in front of her, and she snatched one before Barry set another on top.

"Holy fuck." She mused, turning to Barry to see he had a small smile on his face. "You truly are a hero, Barry Allen. I owe you for this." Barry stood up straight after a moment, all the files now stacked orderly.

"It's the least I could do. You and Cora have helped me a lot when you were at CCPD. Now I can help you." Barry gestured to the files with a smile and Melanie scrunched her face.

"Cora is a sorta. She was usually at STAR Labs rather than CCPD." Barry turned away for a moment to think before nodding. There was a loud knock on the lab door.

Sterling swung the door open, holding the doorframe as he leaned forward. "We got a rob— who..?"

"Uh this is CSI Barry Allen. He works for Central City Police. He's just visiting." Sterling eyed Barry for a moment before gesturing out the door.

"Bring him with. He could help." Barry let out a strained noise, looking to Melanie, who shrugged before picking up a case and following Sterling out of her lab.

•••

Melanie slapped on a pair of black gloves, handing another pair to Barry. She walked towards the shattered window, where the array of expensive jewelry had gone missing. Barry walked towards the front door to the jewelry store, glancing around.

"There's some dirt tracks here. Could be from the robber." Barry gestured to beneath him and Melanie looked over.l before walking towards the door and swung it open. The two walked in to see a handful of cops walking around the jewelry store. There was shattered glass everywhere, and most of the jewelry was missing.

"These footprints look like they could be a man, given the width of the print. But the pressure points look like they were wearing a shoe too big to try and cover up." Melanie knelt down by the tracks, tilting her head and squinted. "The hell..?"

"What is it?" Barry frowned as Dick started to approach the two. He paused when he spotted Barry, the two staring at each other for a moment before they looked around, trying not to act suspicious.

Melanie glanced up at Barry through her lashes when she heard his heartbeat spike for a moment. She turned her head just a bit to see Dick out of her peripheral vision, listening to his heart beat as well. His was relaxed but he still appeared on edge. Phoebe let out a sigh and stood up.

"The robber is wearing a size fifteen book. Pattern looks like Red Wing Shoes." Dick cleared his throat and Melanie turned to him, Barry looking over as well.

"Not just robber." Dick held up a syringe in an evidence bag and handed it to Melanie, who inspected it closely. "Found it with the owner of this store, dead. Cops don't think he had an overdose considering he was robber and the office is a mess. Clear signs of a struggle. The security cameras were disabled, so we don't have any leads on a suspect."

"Get me the tapes for the camera's anyway. Camera's probably got the suspect before they disabled them." Melanie said as she brushed past Dick, who raised a brow. Barry wandered off, aiming his flashlight around as he searched for anymore evidence.

"Whatever you say, detective." He grumbled, following Melanie towards the office.

"It's CSI, right now." She corrected. Dick gave her a quick glance, and she continued. "Detective will make her appearance when I go out and question suspects. Right now, I need to see the victim."

Melanie followed Dick into the office, pausing when she spotted the owner of the jewelry store lying dead on the floor. She set her case down on the desk and clicked it open again, taking out a pair of scissors and a stick.

"Everyone was waiting on you to see the body before we went any further with the vic." Melanie knelt down next to the dead man, lifting up his hand, which was cold to the touch. She dug around for her flashlight, aiming it under the man's finger nails.

"Definitely struggled against his assailant. There's skin underneath the nails. I can run some tests and try and find a match in the system." Melanie dug the skin out from under the dead man's nails with a stick, shoving it into a tiny tube. She looked at the rest of his hand, noticing the bloody knuckles. "He put up a fight."

Melanie set the man's hand down. She stared at him for a long time, an odd expression on her face. It was almost to the point Dick was going to question her until she spoke up. "Look at his shirt." Dick walked over and leaned over Melanie, frowning at the tiny spot of blood near his heart.

Melanie unbuttoned the mans shirt, looking closer to see there was a small hole in the man's chest. "Looks like we know what happened with the syringe." She stated the obvious, moving the man's neck in case there were more holes.

Dick examined the wound on the dead man, "You're right. The killer must have used some kind of tranquilizer to subdue the vic before killing him."

Melanie shrugged, tossing the shirt over the man's chest. "It could also mean that the killer is someone who has access to medical equipment."

"That could be a lead." Dick said as he stood up straight, followed by Melanie. "I'll check with the hospitals and clinics in the area to see if anyone has recently purchased any tranquilizers." Dick waited for a moment, almost expecting Melanie to invite herself along.

"I'm going to head back to my lab and figure out what was in that syringe. We figure that out, we're one step closer to catching this guy. Have them send the body back to my lab, I'll need to go over his body in better lighting." Melanie walked away soon after, and Dick frowned, watching her leave as Barry walked up to him.

"She's great, isn't she?" Barry smiled, Dick turning to him with a confused look. "At her job, I mean. She doesn't usually talk about anything else other than work."

"I've noticed. What are you doing here?" Dick turned to Barry, who fixed his handle on his case strap.

"Oh— Melanie called me. Said she needed help with all the paperwork from the cases before she got here." Dick nodded slowly, sucking on his teeth before turning back to the door. "She knows, by the way."

"Bad idea, Barry."

"It's not my fault. She figured it out. She's really smart, Dick. Like... Really smart." Dick turned to Barry quickly, his brows raised. "Look, she does her own thing. Kinda like you."

"What, she prefers working alone? Right." Barry waited for a moment before shrugging.

"It took her maybe... Maybe a year before she finally let me work with her. It was pretty annoying." Barry sighed, taking another quick glance around the office.

"I gotta get going. How long are you staying?" Dick asked as he started walking out. Barry followed slowly behind.

"Not long. I'll probably meet back up with Melanie at her lab then head back to Central City. I got some problems back at STAR Labs that I need to handle." Dick turned to Barry, raising a brow.

"You need any help with it?" He asked. Barry sighed quietly, shaking his head.

"No, I can handle it in my own. No offense, but I don't think acrobatics will work against this guy." Dick scoffed as they exited the jewelry store, going their separate ways.

•••

Melanie stared down the microscope with a concentrated frown, looking up for a moment to see the compound through the computer screen. Her frown softened as she recognized the chemical.

A loud knock on the lab door startled Melanie, turning to it quickly. She cleared her throat, leaning against the table. "Come in."

Sterling walked into the room, waving a VHS into the air. "I come bearing gifts... And a dead body." He flashed a quick smile, one that Phoebe didn't reciprocate. She walked over to a corner of her lab, dragging out an old TV with a VCR, gesturing for Sterling to walk over. Another officer walked in with a gurney, a black body bag laying on top.

"You can set it on that table right there." Melanie pointed to a table near another window that had a large overhanging light. "I have no idea why there isn't a more sterile room I can do an autopsy on in this place." The officer and Sterling shared a glance.

"Well. We do live in Gotham." Sterling chuckled quietly and Phoebe hummed.

"That seems to be everyone's excuse. When one of you leave, tell Gordon I need a better light and clean supplies." Sterling and the officer shared another look, and the unnamed officer nodded.

"Will do." The officer said before walking out of the lab. Sterling walked over to Melanie, who had plugged in the TV.

"What do you think we'll find?" Sterling wondered as he handed Melanie the tape. She turned the TV on and shrugged, slipping the VHS into the VCR.

"Probably nothing. Maybe the killer was stupid and overdosed the owner before disabling the cameras." Melanie clicked the play button on the TV remote, taking a step back and crossed her arms as she watched the footage.

"I've worked here for almost a decade now. Been here since I was 18 and just an intern. One thing I've learned is that Gotham murderers are messy, but they still get away most of the time." Sterling sighed, crossing his arms as he shook his head. "So many families have never found the killer of their loved one."

"That's because your previous CSI sucked." Sterling side eyed Melanie, who turned to him. "I did my research. I know the Riddler used to work here before he got locked up. And Harold Allnut. He wasn't very good at solving cases."

"No, he wasn't. I was just starting here when Edward worked here. He wasn't a formal CSI, none of them really were. You might be the first CSI we've had in decades." Sterling said and Melanie scoffed, scratching her forehead.

"Good to know that I'm the only one capable of doing the job right in this lab." Sterling sucked in a sharp breath, humming.

"You sure sound like it." Melanie have Sterling a quick glare before he pointed to the screen. "There he is."

Melanie turned to the TV, watching closely as a hooded figure slammed a crowbar into the jewelry stores door. She watched another screen of the camera to see the owner rush out of his office, incoherently scream before running back in.

The robber was quick to run after the owner, crashing through the door and ran awkwardly from using the large shoes. In the office, the security footage caught the figure tackling the man before he could call for help. The two wrestled around, and eventually, the hood flew off.

The killer raised a syringe into the air before jamming it into the owner's chest. The man, again, incoherently yelled before he fell limp, but was still moving.

"He's not dead yet. What killed him?" Sterling took a step closer to the TV as Melanie did, glaring at the screen. The killer pulled out another syringe and inject himself with it. Melanie and Sterling shared a confused look to one another as the killer pocketed the syringe.

"What the fuck was that? Heroin?" Sterling questioned and Melanie sat up straight, her arms tightening around her as a disturbed shiver ran up her spine.

The killer turned to the camera, but was still looking down just enough that they couldn't get a good look at his face. "What kind of messed up fuck injects someone with a sedative then shoots himself up with heroin?" Sterling continued to ask as he began pacing, still watching the TV.

"It's not heroin. It slows down the brain function and would have made him weak in the legs. Whatever he just took made him into some robot. Look at the way he's moving." Sterling watched the man move in an odd way, almost as if he was being controlled with a joystick. "Look here."

Melanie paused the footage and pointed at the killer's ear. "He's wearing an earpiece. There's probably a second person in on the job, could be forcing him to do this."

The killers lips moved for a moment and he waited. Another moment passed before he picked up his crowbar and slammed it into the jewelry owners side, Melanie turning to the body bag and frowned in confusion.

"I must have missed that injury." She mumbled and turned back to the TV just as the killer disabled the cameras. "That hit wasn't strong enough to break a rib and puncture the victim's lung. And that drug was just a paralytic."

"Did you figure out what it was?" Sterling asked and Melanie nodded, walking back to her computer.

"It's Suxamethonium chloride. There's only two kinds of medication for it. Quelicin and Anectine, it's used for surgeries. I just need to figure out which one specifically was used to narrow down our suspects." Melanie gestured to her computer screen as Sterling nodded.

"I guess I'll leave you to that, then. There's some witnesses in the interrogation rooms that I need to question. And I don't want to be here to watch you carve open a dead guy. Try and figure out what that killer injected himself with, I'll bring Grayson down here."

"No need. I can handle this on my own." Melanie stated and Sterling watched her for a minute, raising his brows. "He's a detective, Boone. He doesn't have the same qualifications as a CSI."

"Whatever you say, detective." Sterling saluted Melanie before walking out of the lab. She watched him for a moment before turning back to her computer.

"It's CSI." She mumbled, grabbing a box of gloves and slipped them on. She moved towards the body bag, throwing on an apron before unzipping the bag.

She stared down at the dead man for a moment before looking back at the TV, then to her computer, which still displayed the paralytic that the man in front of her had been injected with. She looked back down at the victim as she picked up her scalpel.