This is my first B99 fic so I hope you give it a chance. Also posted on AO3.

It was well after midnight by the time Jake arrived back at the nine-nine after he'd been out following a lead with Boyle. The lead was a dead end so Boyle had already left and he was just going to grab his belongings from his desk and head home for the night but when he stepped off the elevator it was to find Santiago asleep on her desk.

As he walked closer, Jake couldn't help but laugh at how cute she looked, pen still in hand, her face pressed against the file she'd been working on.

Jake gently removed the pen from her hand, not wanting her to ruin her file, he could see that the page was creased where she was lying and she'd already be upset enough about that. He needed to wake her now, make her go home to get some proper sleep before her shift tomorrow morning.

He could wake her gently, a slight nudge to her shoulder or whispered words would do the trick, but where would the fun be in that? He circled back around to his desk, sitting down before he cleared a small space by his computer. He then took the biggest file he could find, raised it above his head and slammed it down on the clear space, a loud bang ringing out through the nine-nine.

The noise drew the looks of the several officers and detectives who had the night shift but it also had the desired affect when Santiago jolted awake at her desk, eyes flying around the room in search of the loud noise. She knew she'd found the source when she saw Peralta looking at her across their desks, a huge grin on his face as he took in her startled form.

Santiago glared at Peralta before she looked down and groaned, realising she'd not only fallen asleep during paperwork, but she'd also crinkled one of the pages due to her face resting on it.

Where was her pen? It was back in its usual spot which would've been impossible if she'd fallen asleep holding it like she thought she had. Had Jake moved it? She grabbed it anyway, needing to finish this paperwork before she went home but before she could continue with her work, Jake spoke.

"Home time, Santiago."

"Soon."

Peralta didn't reply immediately so she looked up only to find him giving her a look that clearly said that he didn't believe her.

"I just need to finish this."

"You can finish that in the morning, when you're well rested and don't look like you're about to fall asleep again."

She was about to reply, saying she was perfectly fine, but a yawn stopped her response.

Peralta was smirking at her now and she knew she'd lost, "fine, I'll go home now."

"Good," he grinned, rising immediately to pack up his belongings before he was standing next to her desk, looking at her expectantly.

"What are you doing?" Santiago asked, looking up at him curiously as she went about her daily ritual of shutting down her computer and tidying up her desk, ready for the next day of work.

"I'm waiting for you," he replied like it was the most obvious thing in the world.

"I'll just be a few more minutes and then I'll leave, there's no need to wait, I'll see you in the morning."

"I'm going to drive you home."

Peralta could see she was going to argue so he spoke again, "you're exhausted, just accept the offer, I'll give you a ride home."

Amy was about to argue again but he did have a point, she was exhausted and it would be a lot easier and safer to just accept his offer.

"Fine," she grumbled, grabbing the last of her belongings and Peralta grinned at her again and then they walked out of the precinct together.

That night, she even let him walk her to her door at his insistence that he wanted to make sure she made it all the way home without falling asleep after she'd fallen asleep again on the car ride to her place. She couldn't help but smile as she shut the door behind him, wondering when he'd gone from the annoying guy she worked with, to her friend, to someone she trusted and could rely on no matter what.

These rides home became a common thing for them. On nights where they were working late, when one of them was exhausted from long work hours, the other would make sure they got home okay. This didn't happen too often but it was often enough that there were no longer arguments when it was time to leave and an offer of a ride home was given. Even once, Santiago had convinced Jake to let her take him home when he was ill and she'd come back after lunch to find him hunched over his files, trying to work, even though he had to stop every few minutes to cough or grab a tissue.

It was long after this new ritual had began that Santiago found herself being called into the Captain's office.

"Santiago, a word."

"Is everything okay, Captain?" she asked nervously, trying to figure out if she'd done anything wrong.

"You and Peralta need to go home and get some proper sleep."

"But, Captain-" He cut her off.

"Not buts, Detective, I know you both spent the night here and you may have gotten a few hours of sleep on the break room couch but Peralta hasn't slept at all so you both need to go home and take a break." She wasn't sure how the Captain had known all that was true but that didn't matter, they had a case to work and she didn't want to give up on it just because they were slightly sleep deprived.

"But the case-" He cut her off again.

"Boyle and Rosa are going to take over your case until tomorrow morning when you're both fully rested and can actually be some help."

Santiago opened her mouth to protest but decided against, not wanting to argue with the captain even if she didn't agree with what his orders were. Well, maybe she did, they were both exhausted, having gotten only a few hours of sleep over the last few nights as well as the (mostly) sleepless night last night.

"Yes sir," Amy replied, returning sullenly to her desk but she realised that their orders were probably for the best when she saw Peralta slap himself in the face to try to wake himself up.

"Home time," Santiago said, covering another yawn as she realised just how tired she was.

"But the case?" Jake asked, noticing it was Amy's no-nonsense, we're leaving now, you're tired, voice, the same one he's used on her to get her to go home to rest as well.

"Holt's orders, we're both to go home and sleep, Rosa and Boyle are going to take over the case while we're gone."

Jake thought about arguing but decided against it. As much as he wanted to be working this case, he really was tired and since it was Amy telling him to go home, he felt he should listen to her with this new routine they've formed together.

"Who's driving who home?" Peralta asked, gathering up his belongings as Amy did the same. Amy was about to reply that she was driving when Boyle walked up to Jake's desk, interrupting them.

"Don't worry, Jakey, I'll take care of the case until you get back," Boyle said, now hovering at the side of Jake's desk, waiting patiently for Jake to hand over the case files while Santiago gave her folders to Rosa.

"Thanks," Amy said, smiling at them both, getting no reply from Rosa but a big grin from Charles.

"I'm driving," Santiago said when they were in the elevator, heading down to their parked cars.

"Why you? You're tired too?"

"I'm not the one who's currently leaning against the wall wearing sunglasses in an attempt to hide the fact that their eyes are closed."

"They are not," Jake replied, his eyes still closed but Amy didn't need to know that.

"Jake!" she replied, pulling the glasses from his face, proving that his eyes were in fact closed.

"Fine," he acquiesced, struggling to push himself off the wall as the elevator doors opened. He knew that she'd had a few hours sleep in the break room and he really shouldn't be driving in the state he's currently in.

Peralta fell asleep on the way to his place and it took Amy hitting him rather hard on the arm to finally rouse him from his sleep so he could make it into his building.

"I'm fine," Peralta said as he stumbled from her car and there was no way in his current state that she'd let him walk up to his apartment alone, afraid that he'd fall asleep on the way.

He managed to make it into his apartment in the end with little help from Amy and she was very impressed that he managed to unlock his door with hardly any trouble. She followed him in, not really thinking about what she was doing, she'd done this multiple times before as had he with her (they were both workaholics so they'd had to drive each other home a few times) and she burst out laughing when he walked straight over to his bed and fell face first onto it.

"Are you not even going to change?" Amy asked, watching in amusement as he struggled to turn over so he could look at her as he spoke.

"You want to see me undress?" he asked in reply, giving her a suggestive look that had her blushing despite herself.

Santiago managed to compose herself before she replied, her voice steady as she replied, "at least take your shoes off before you sleep."

Peralta made quick work of kicking off his shoes, letting them fall of the end of the bed. She tried not to look as he next removed his pants, leaving him in boxers and his shirt but then he managed to maneuver the tie over his head and unbutton his shirt and before Amy had a chance to really appreciate that fact that he was now only in boxers, he was under the covers.

Amy yawned again, not being able to help it in her tired state, and realised that she needed to go home so she could get some much needed sleep too.

"Wait," said Jake, sitting up like he'd just realised something, the sheet pooling around his hips, giving Santiago a nice view of his chest this time.

"What?"

"Who's going to drive you home?"

Amy laughed, he really must be tired,"I'm going to drive myself home."

"But you can't."

She furrowed her eyebrows, not understanding what he was trying to say.

"I mean you're tired, and I'm meant to drive you home if you're tired, but I can't because you've already driven me home."

"I thought we established that you were more tired than I was so it was my turn to drive today."

Jake stopped and stared at her, looking like he was thinking really hard, trying to figure out what they should do next.

"Jake, just go to sleep, I'll see you tomorrow." She gave him one last smile as she spoke, the smile that always slipped free when he was doing something cute, like the confused look he was currently giving her as he tried to work out how she was going to get home without her having to drive in her current state.

"Wait!" he said again, louder this time, "what if you…" He trailed off, not entirely sure if he should ask what he was about to incase it crossed some sort of line in the friendship they'd now developed. But she was tired, and so was he, and he this couldn't hurt them, right?

"What if what?" she asked, not entirely sure why her heart had started beating loudly in her chest but it was probably something to do with the look Jake was giving her now (or the fact he was shirtless).

He looked like he was debating on whether or not to say what he'd been thinking but then he'd decided and was talking again, "what if you just stay here?"

"What?" Santiago replied, voice higher than she would've liked it to be.

"I can't drive you home so why not just stay here?"

"You mean…" she trailed off, not entirely sure how to ask him if he meant they were to share his bed.

"It's just sleeping," he shrugged, trying to act like it would be no big deal to share a bed with the person you secretly like (and are quite possibly in love with)

Santiago was hesitating and Jake took that as a good sign, that she hadn't immediately said no, so he leaned over the side of his bed and grabbed the first t-shirt he could reach. After quickly pressing it to his face to make sure it didn't smell, he tossed it at her, "here, you can wear this."

"It's clean, don't worry," Peralta said when he saw her eyeing the shirt now clasped in her hands. Amy hadn't been worried about that fact though (well, maybe a bit) but she was more concerned with the fact that Jake was asking her to wear his clothes.

She thought about it for a minute but her level of tiredness made the decision for her, "fine, I'll stay, but only because I'm too tired to leave."

Jake grinned in response.

Amy changed quickly before she could change her mind about this whole idea but she did really need sleep and she probably shouldn't be driving with how tired she was either.

Jake had made room for her on one side of the bed and she awkwardly climbed in, glad that the shirt he'd given her was long enough to at least come to her mid thigh so he didn't get a view of anything he hadn't seen before.

Once she was in the bed she looked over and realised that Jake was already asleep and she founded herself both relieved and disappointed at the discovery.

Amy settled down in his bed, surprised and how she felt immediately comfortable lying next to him in it. As she slowly drifted to sleep, the day blurring into unconsciousness as she was surrounded by everything Jake Peralta, she couldn't help but feel like they'd crossed a line in their friendship. And it may not have been just this simple act of sharing a bed together but this was what was probably going to tip them over that line if anything was going to happen, if Jake what she felt too.

The rides home during late nights at work may have started innocently enough but somewhere along the line they had morphed into something more, something that led to lingering looks, soft touches, and the feeling that there was something going on between them that was more than just the friendship of two colleagues.

The words he'd said before, it's just sleeping, popped back into her head and that may be true for right now but who knows what could happen when they woke up.

Thoughts? I may write a second chapter to this if anyone is interested.

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