A/N: I got this idea from the random pairing generator with the prompt of Skyfire/Sunstreaker/Sadism. I am treading as carefully and respectfully as I can. I've read over Sunstreaker's bio to refresh my memory and I've found this is not an impossible scenario.

Chapter 1

"This is the fifth time in two weeks you've been in here. Just what kind of experiments are you doing in that lab of yours?" First Aid tried to keep his tone calm and light, just to put Skyfire at ease.

For how large the shuttle was, his plating was held in a way that made him seem small. Perhaps it was the embarrassment of having to come in for yet another repair. He'd been in here more than Wheeljack, which was a huge –and dubious -accomplishment. First Aid relayed as much, but Skyfire only made an odd grimace, testing out his wrist joint once the medic was done.

Someone had laughed at his half-hearted joke though, and he was sitting on the next berth over, his optics watching them intently. First Aid wouldn't have let Sunstreaker stay, but even as a medic, he was admittedly frightened of the yellow mech. Only Ratchet seemed to be able to get either twin to listen, but Sunstreaker hadn't wanted Ratchet to take care of Skyfire's wounds.

First Aid still tried to insist though after they came in on the second injury. A ripped fuel line was a bit advanced for him. "Are you sure? Ratchet would be more qualified to help you."

Skyfire had held his leaking side, energon seeping between his fingers. His expression was cast in a painful frown, and he'd glanced at Sunstreaker standing by his side, whose own face completely blasé. "We are sure." He still managed to smile, even if it hurt. "You're more than capable."

First Aid had been flattered by the faith put in him, and stopped questioning why they never went to Ratchet after that. These continued injuries did bother him, and wondered just how dangerous the labs really were. Maybe it wasn't just Wheeljack that gave it a bad reputation.

"He walked into another shelf." Sunstreaker piped in. He sauntered from the berth to stand beside Skyfire, and peered down at his wrist with disinterest. Then his gaze flickered to the shuttle's face. "You're such a klutz; can't you go a day without hurting yourself? What would you do without me around?"

First Aid found the words harsh, but Skyfire only shrugged it off and returned Sunstreaker's surly glare with a fond smile. Perhaps Skyfire just had thicker plating to deal with the moods.

"You're right."

The yellow mech straightened up, his chest puffing out haughtily. "Of course I am." When Skyfire reached his arm, Sunstreaker turned away without a glance back. "You're fine, we're leaving." There was a finality to his voice, and Skyfire rose to obey it.

First Aid stopped him though. "Try and be more careful, I'd hate for this to be a regular occurrence."

Skyfire rumbled gently. "Your concern is duly noted, and I will try my best."

"Let's go." Sunstreaker said annoyed. First Aid saw him standing by the door, his arms crossed and a scowl on his lips. Despite his unpleasant attitude, he could see from how the light glinted on his armor- showing off the lines and seams of his protoform underneath- and the blue blaze of his optics-so bright and fierce- why mechs found him attractive.

He certainly didn't fault Skyfire for wanting him. The real surprise was that Sunstreaker wanted him back.

For First Aid, seeing something with his own optics always grounded it in reality, and during the past two weeks he'd seen their interactions first-hand rather than relying on second-hand gossip. Which was a lot, given that one of the most notorious berth hoppers on the Ark was now unavailable.

Everyone thought it was a joke, and had waited for the punchline. And waited…and waited…but when there was no smug boasting or spark-broken shuttle skulking about, they all knew the joke was on them instead.

Honestly, no one had seen it coming-except perhaps Sideswipe, but he wasn't saying anything.

So while First Aid knew that Sunstreaker and Skyfire were together, it wasn't until after Sunstreaker had brushed his servo over Skyfire's repaired lip-having split it by a minor kickback from a tool-did it sink in. Sure, Sunstreaker didn't dare let sentimentality shine through his expression when he did it, but it was reassuring to know that he was watching out for the shuttle.

Why else would he bring Skyfire to the medbay?

With that reminder, First Aid filed away his report with the other accidents that Skyfire had been unlucky enough to have. This time it was a dislocated wrist; thankfully the fibers and filaments didn't need to be replaced, and the joint was practically good as new once it was popped back into place. Relatively minor compared to some of the other injuries the shuttle had come in with.

Though it did make him nervous about the continued safety of their scientists; were things up to par? Were there any other hazards, like sharp points or improperly handled substances? How long would it take before Wheeljack got injured by something which wasn't an explosion?

First Aid waited until his shift was over before he made his way to the labs. He knew he should go to one of the commanders, but there was no point unless he could bring them any findings. He didn't want to bother them unless he had something.

So bracing himself, the medic stepped past the sliding doors. He faltered immediately. It…didn't look like a death trap. Along the walls were shelves covered with glass that kept the beakers and marked chemicals out of reach, and the keypad on the cabinets only added a level of security.

A security which didn't help Red Alert's paranoia, as both the science labs and the medbay lacked cameras inside; neither Ratchet nor Perceptor were all that keen on being spied on doing their jobs, and they both used the excuse of 'one slip is all it takes' to have the cameras moved to outside their respective work spaces.

Speaking of the microscope, First Aid saw him taking notes of a sample slide he'd likely examined in his alt-mode. So wrapped up in his work, he didn't notice First Aid until the medic cleared his intakes.

Perceptor jumped, his helm snapping in the medic's direction. Panic subsided when he saw who was there. "Oh, it's you. What can I help you with, First Aid?"

The medic inspected the room, his hidden optics sweeping over the clean floors and tidy tables. There didn't appear to be a speck of dust or dirt anywhere. The room was positively sterile. "I'm here about safety. Are there any jutting or sharp edges? Any loose tiles that a bot could trip on?"

Perceptor stiffened, his faceplate freezing. "I keep this lab completely up to date on safety measures." He said a tad frostily. "Who is insinuating that this is a health hazard?"

"No one." First Aid said hastily, his servos held in placation. "I didn't mean to imply it was; it's just…well, there has been several…accidents that have happened in here."

Perceptor's defensiveness slowly turned to confusion. "Accidents? Aside from Wheeljack's explosions, there have not been any accidents."

First Aid frowned. What? That couldn't be right. "Are you sure?" Perceptor gave him a hard stare and the medic backed down. "It's just…well- someone's been coming into the medbay saying they've gotten hurt doing work in the lab."

"If they've been hurt, it wasn't in here." Perceptor insisted. "All mechs who want to enter must sign in." he nodded to the door, where First Aid knew was an electronic keypad that only granted access to those who put in their ID chip. Another little feature of added security that Red Alert didn't think was enough.

"And in addition," Perceptor continued, "Red Alert certainly would have reported it if there was any accidents or indiscretions caught on camera."

"I see." First Aid said softly. It was now overwhelmingly obvious that both Skyfire and Sunstreaker had lied to him. Why would they do that? What was there to hide about the origin of Skyfire's injuries? "Do you know where Skyfire would be? I'd like to speak with him."

Perceptor huffed. "My word isn't good enough?"

"No, nothing like that!" First Aid exclaimed. "It's about something else. Believe me, I now fully know you keep this place in top-shape."

For a moment, Perceptor straightened up proudly. But then, his lips were pulled into a frown. "I don't know where Skyfire spends his time. At least not anymore. You should ask Sunstreaker."

"Sunstreaker?"

Perceptor nodded. "He's always walking Skyfire here and waiting outside when his shift is over."

"I…I see." First Aid repeated, his voice even softer. He cleared his vents and nodded at him. "Thank you for your time. I should go."

He quickly ducked out of the room, his spark thrumming in its chamber. Something suspicious was definitely going on. First Aid was never one to believe the worst, but the fact the evidence was stacking up to something which didn't make sense? Why would they lie to him?

'They could get away with it if it was only me they planned on telling, if they thought I wouldn't dig.' That was a logical conclusion, but it led to more questions. He wouldn't know the full story unless he asked the source; but if what Perceptor said was true, he wouldn't be able to track Skyfire down. Not like he could have beforehand. First Aid felt guilty he'd gotten to know more of Skyfire's anatomy than about his demeanour.

As he didn't know where Skyfire's room was, and he wasn't all that enthused about speaking with Sunstreaker, First Aid went off in search of Sideswipe. Even if the red twin didn't have the answers he was searching for, First Aid was certain he'd be able to get something.

He got lucky on the first try, and the medic politely asked to speak with Sideswipe when he found him in the rec room. The mechs at the table smirked and Sideswipe grinned as he followed First Aid out of the room. This was not a conversation he wanted anyone overhearing.

Sideswipe leaned on one leg, his arms crossed casually. "What do you want?" he tilted his helm, a sly grin starting to curl at his lip. "If you're looking for a good time-"

"It's not that." First Aid interrupted flustered. "I was wondering if you knew where Skyfire's room was."

Sideswipe stared at him. "Why the slag would I know that? Sunny's the one he's with."

"I'm aware of that. Since you're Sunstreaker's brother, I figured he would tell you where Skyfire's room was located." First Aid explained.

Sideswipe tilted his helm again, but this time it was from confusion. "Sunny moved out two weeks ago. He's living with Skyfire now," he shrugged, "and he doesn't tell my anything about their re-la-tion-ship," he stressed the word as though it were a joke, "which I don't really wanna know about anyway."

First Aid vented as he reached another dead end. "Thank you for your-" he stopped suddenly, two words stuck in his processor. "Two weeks? That's how long Sunstreaker's been living with Skyfire?"

Sideswipe raised an optic ridge. "Thought I just said that? If you're processor's starting to rust then where's that going to leave the rest of us?"

First Aid shrank in on himself. "Perhaps you're right. I should check my modules. It doesn't hurt to be thorough." It was more than just a platitude, and First Aid repeated it to himself as he made his way back to the medbay.

Suspicion churned his stomach tank. Was he really letting himself go down this road? What if he was wrong? First Aid vented again and brought out Skyfire's recent medical files. As he looked over each incident with a new perspective in mind, a disturbing pattern emerged.

Injury 1: a damaged pede.

Injury 2: a torn energon line.

Injury 3: a split lip.

Injury 4: a cracked optic.

Injury 5: a dislocated wrist.

Any one of those wouldn't have been suspicious by itself, but all together? And just so happened to coincide with the time frame Sunstreaker and Skyfire had been living together? Throw in the fact they both lied about where it happened, and it was starting to look suspiciously like a cover-up.

'Is…Is…' First Aid didn't want to think it, but the evidence was beginning to pile up. If he got confirmation, then what was going to happen? 'Is Sunstreaker hurting Skyfire?'