For the third night in a row, Claire Benson was startled awake by the sounds coming from the left wall of her tiny New York apartment.

It was the same wall that her head was situated at, so she woke up instantly.

She blinked groggily a few times, immediately registered the absence of light from behind her curtains, and attributed her conscious state to her new neighbor's late-night activities, whatever those might be. The sound that had woken her up was a very unneighborly THUMP loud enough to have jerked her out of her REM sleep.

Claire checked her phone on instinct. It was 2 in the fucking a.m.

She closed her eyes again, hoping that the noises had ceased. She had them closed for a full three seconds before a new cacophony of sounds followed them. An odd combination of clanging and hard, thudding noises. She reopened her eyes, now officially annoyed. What could New Neighbor be doing that required so much fuss in the middle of the night?

New Neighbor had moved into apartment 9C, right next door, about a week ago. For the longest time, it had been empty. Claire wished she'd appreciated those blissful, quiet months a little more, having never had to experience the annoyance of a loud neighbor. She worked long shifts at New York-Presbytarian Hospital, so opportunities for sleep were few and far between. And boy, did she need it.

New Neighbor had been quick and efficient to move in, and Claire hadn't gotten a good look at her. Only a glimpse of a few dark red curls before the door was slammed shut behind her. She didn't seem like the friendly bake-you-cookies type, which was fine with Claire, because her baking skills were shit.

There was a final THUD, and the noises stopped suddenly.

Maybe they're getting robbed.

Claire briefly entertained this idea. She wondered if she should get up and check on New Neighbor (read: tell them to stop making so much fucking noise), but quickly vetoed that idea because a) she was tired, b) she wasn't wearing pants, and c) the noises had stopped momentarily.

She stared at the ceiling, wondering what to do, waiting for more noises. They didn't come. A few minutes passed. She closed her eyes again. Then, another muffled sound came from New Neighbor's wall. This sound was different from the others; it was a groan.

Or a moan. A very long, drawn-out moan. A sudden realization swept over her. She hadn't realized New Neighbor had a roommate, but maybe it was her boyfriend. Or a total stranger. More moans followed.

Oh, god. Please tell me they're going to stop soon.

Claire wasn't sure what these new sounds had to do with the harsh ones from earlier, but she didn't have the heart to care. Instead, she muffled a groan as she threw the covers over her head and buried herself in her bed. Fortunately, no new sounds followed. For the third time, she let her eyes flutter shut. She laid still for a couple of seconds, feeling tiredness cloud her mind and weigh down her limbs.

Then, just as she was feeling herself start to slip into unconsciousness, a particularly loud moan dragged her awake. Annoyance fueled a burst of energy that made her toss her covers to the side and storm out of her apartment and face the door of apartment 9C.

Claire pounded on the door without thinking twice, her knuckles stinging slightly from the force. When no response came for several seconds, she yelled, "Hey! I know you're in there!"

She raised her fist to knock again. Before her knuckles made contact with the door, it swung open.

Claire froze. In the doorway stood a really— no, wait. She had— okay, there's no way to say this subtly. She was goddamn attractive. Claire hadn't been expecting a total skeezeball, but she certainly hadn't been expecting this. New Neighbor's red hair dropped past her shoulders, falling in wavy curls. Her eyes were light green and narrowed dangerously. Her skin was smooth and…

"Done staring?" New Neighbor asked. There was a small frown on her face. Which didn't make sense, because Claire was supposed to be the annoyed one.

"I wasn't—"

Claire stopped, because she clearly was, and denying it would only make her look foolish. She cleared her throat, which suddenly seemed dry. She was not going to be that kind of girl who excused shitty neighborly behavior just because they were hot. Really fucking hot.

She noticed that New Neighbor seemed to be giving her the once-over as well. Her cold expression betrayed nothing. Claire was suddenly reminded of the fact that she wasn't wearing pants, and her shirt didn't cover much. A rush of heat shot to her cheeks, but she forced herself to not be flustered by her current state of dress.

"Well?" New Neighbor asked, waiting for Claire's explanation for knocking on her door so late at night.

"Sorry, I—" Wait. Why was she apologizing? Her resolve firmed up.

"Listen," Claire started again, a rush of anger and "it's 2 a.m. and this is the third time I'm waking up to noises from your end. I don't know what the fuck you're doing in there and I don't really care, but I'm trying to sleep. So if you could knock it down a few thousand notches, I'd really appreciate it."

Great. Now she sounded like a bitch.

Before Claire could apologize, there was another moan from within the apartment. Claire found this odd, as she'd previously thought they were having sex in there. But now she wondered if there was something more strange going on.

She frowned. "What was that?"

"That's none of your business," New Neighbor said curtly, not bothering to soften the words. "As for the noise complaint, rest assured that it won't happen again. Have a nice night."

With that, the door slammed shut.

Claire, despite her intention to not appear foolish, felt very much so as she was left standing in the empty hallway, staring at a closed door.

True to her word, there were no more disturbing noises waking Claire up in the early hours of the morning. There were no noises at all, actually. No shuffling, no moving things around, no general existing-here sounds coming from apartment 9C.

She couldn't stop thinking about her, though. She was insanely curious about her— Who was she? What did she do? What caused those noises? Their brief encounter had left much to the imagination. New Neighbor was mysterious, and Claire loved a good mystery. More to the point, she liked knowing things, so when there was something she wanted to find out, she usually got it. She was into detective novels and true crime podcasts. She was pretty observant, too, and sneaky when she wanted to be.

She'd wanted to be a detective, actually, but her parents' sky-high expectations and constant badgering had forced her into the medical field. It wasn't that Claire hated medicine— she'd grown to enjoy it over the years. The late nights studying and her hard work had finally paid off, and she had a six-figure salary and a nice apartment in New York. But that was beside the point.

Claire hadn't seen her mysterious neighbor since that night of confrontation. Maybe New Neighbor had only been planning to stay a couple of weeks and move out. Claire had almost accepted that she'd never unravel the mystery when one day they bumped into each other in the hallway.

Claire was returning from a particularly hard shift. She'd pulled a 24-hour shift and was returning at 4 in the morning. She was dead tired, running on about a half hour's worth of sleep, and eager to collapse on her bed once she got home. She was pretty sure she looked like crap. Hair tied in a messy ponytail, dark circles under her eyes, and rumpled clothing.

Despite this, she stopped in her tracks when she saw a redhead exiting apartment 9C. In contrast, New Neighbor looked as put-together as ever. She was casual in jeans and a fashionable cream coat, hair perfectly styled, and wearing light makeup. Claire hadn't meant to stop and stare, but New Neighbor had slowed as well.

"Hi," Claire said, not sure if they should be ignoring each other.

She cursed herself. She couldn't expect to be on good terms with the person who she'd yelled at with no pants on at 2 in the morning. She winced as she recalled the details. Not exactly her best moment.

"Morning," New Neighbor said coolly. It wasn't friendly, per se, but there was no resentment in her tone.

There was an awkward moment that seemed to stretch and pull, until the tension was unbearable. New Neighbor didn't seem uncomfortable, but Claire shifted her weight on her toes.

"Sorry about the other night," she began. "I was tired and kind of a bitch."

"You were."

Even though Claire had been the one to apologize first, the cold agreement ignited a fire in her. "To be fair, though, you were the bitch first."

"Wow. Stellar apology."

Claire sighed, having regretted the words the instant they popped out of her mouth. Shit. She'd always found it hard to apologize to people, even when she knew they deserved it. Swallowing her pride, she forced the words out. "Really, though, I'm sorry. For real. I shouldn't have been so rude. And I appreciate it, you know, keeping the noise level down."

New Neighbor considered her for a moment. Claire fidgeted again, not liking the weight of her gaze felt a little like being stared down by a lethal predator. "At least you're wearing pants this time," she finally remarked, the cold look in her eyes thawing a little. Not accepting the apology, but not refusing it, either.

Claire bit down the blush that threatened to creep up her neck. "Yeah. Sorry you had to see that."

"Do me a favor. Stop saying sorry."

Claire apologized a lot when she was nervous. She hoped that New Neighbor wouldn't notice, but it was evident that she had.

"Sorr— I mean, okay." She coughed, trying to think of something to say. "So, you just moved in, huh? Staying for long?"

"I'm in town on a business trip," said New Neighbor, "so it depends."

"Oh, what kind of business?"

"It's very dull. I'm sure you won't be interested in hearing all the boring details."

Part of Claire wanted to object, but she wasn't sure whether or not to press it. "I guess you're right."

There went that avenue of conversation. There was another tense silence. Neither of them made a move to leave. Claire opened her mouth, a sentence forming on her tongue about having to get back to her apartment.

Before it could leave her lips, New Neighbor asked, "Where are you coming from so early in the morning?"

"The hospital." Automatically, Claire pointed a thumb behind her shoulder in a general direction of where it was, realizing too late it was a stupid and pointless gesture. She put her hand down. "I work at New York-Presbytarian."

New Neighbor's eyebrows lifted. "You're a doctor?"

"Yeah, I'm in general surgery."

"You're young."

Claire bristled, used to having that same phrase be leveled against her by her older, white male colleagues. Usually in a more pointed, less blunt way, but the words were triggering nonetheless.

New Neighbor cracked a small smile. That surprised Claire. Maybe she was human after all. "Relax. I didn't mean it as an insult."

Claire shook her head, dropping the hard glare that had somehow twisted itself into her features reflexively. "Sorry—"

New Neighbor shot her a warning look.

Claire realized, biting down the instinct to apologize again. "Yeah, I did it again. Anyway, I'm new, I guess. Just finished my residency a couple years ago."

"So, long shift?" New Neighbor guessed, gesturing at her. Claire guessed she was referring to the fact that she looked like she'd walked off the set of The Walking Dead.

"24 hours."

"That's rough."

"I'm ready to drop," Claire admitted.

"Well," New Neighbor moved out of the way, "don't let me get in the way of you and your bed."

Claire smiled, grateful for a natural way for her to leave the conversation. Mumbling a vague goodbye, she waved her keys as she trudged towards her apartment and unlocked the door, immediately throwing herself onto her couch and blacking out.

When she woke up, she realized that through that whole interaction, she hadn't managed to figure out anything about New Neighbor. Why was she awake so early in the morning?

She hadn't even gotten a name.

The next time, Claire was determined to remedy that.

They bumped into each other. Same time, same place. Claire was just in the process of unlocking her door when the door to apartment 9C opened. New Neighbor, it seemed, was an early bird.

They stared at each other in surprise before exchanging the customary neighborly greetings.

"I never got your name," Claire said.

"Natasha," the woman said.

"Just Natasha?" Claire prodded. She liked how it sounded on her tongue. It suited her. The name was Russian, which made sense. "No last name?"

"I was born without one. I'm like Beyonce."

Claire smiled at the joke, both amused and surprised. Natasha didn't come across like the joking type. It made some of her cold exterior chip away. "You sing like Beyonce?"

"Can't have you knowing all my secrets, can we?" A shadow of a smirk flitted across her mouth. "Now it's your turn. What should I call you?"

"Claire." She mimicked Natasha's monoverbal response.

"Dr. Claire?"

"Benson," Claire corrected automatically, then frowned. She'd tricked her into revealing her full name. Which didn't seem very fair, since Claire had only been given one of them.

"Claire Benson," Natasha repeated, a hard to read glint in her eye, and Claire tried to hide the shiver that shot down her spine when she said her name.

"Hey, Harry."

The custodian grunted as Claire passed by. He wasn't the friendliest, but she knew he was a sweetheart. She'd even met his kids once; a girl and a boy. They were adorable. Also, she always made a point of getting to know the people she saw frequently and learn their names.

Claire had pulled another night shift, so she'd walked home in a sleepy daze, trying to keep her eyes open. She hadn't had the energy to change out of her light blue scrubs. The lower half was splattered with dried blood, but the sun hadn't risen yet, so she didn't get many odd looks.

Waving a tired goodbye to Harry, Claire reached the elevators and pressed the button. When one arrived with a ding, she stepped in, turned, and waited for the doors to close.

Before they could shut completely, a quick, lithe figure slipped in between the crack, the movement forcing the doors to reopen. Claire felt a quick stab of annoyance at whoever made her experience a few seconds' delay on her way to her room. Then she caught a flash of familiar red hair and her fatigue dissipated like spilled water on a hot day. Her heart sped up, and her stomach clenched and unclenched.

"Morning, Doc," Natasha said with a nod, stepping inside and facing the closing doors.

Claire matched her neutral tone. "Morning."

Natasha stood a foot or two in front of her. A friendly distance. Not close enough to prompt a conversation, but not so far that it unwelcomed one, either. Claire noticed she was wearing workout clothes: black compression leggings, running sneakers, and an oversized dark red hoodie. She couldn't help noticing how toned her legs were, and looked away quickly.

Done staring?

Claire lived on the highest floor, and the elevator moved at glacial pace. Another silence stretched between them. Claire was hyper-aware of the space Natasha was taking up to her left. She debated starting a conversation, but what would she say? Everything that came to her head sounded stupid.

"Long shift again?" Natasha said without turning around

"Yep." Claire winced at her voice, which was rough with exhaustion. "So what's your excuse for being awake at 4 a.m.?"

"I went on a run."

Claire was a runner as well, but she couldn't believe anyone would get up so early just for a session. "At 4 a.m.?" she echoed disbelievingly. "You're either a masochist or you ran cross country in high school."

It was hard to tell if she'd drawn a smile out of her, but Claire saw her shrug. "I like the quiet. It's one of the few times that it's peaceful in New York."

Claire glanced at the elevator. It was halfway to their floor. "You go often?"

Probably sensing that the conversation wasn't going to fizzle out, Natasha turned to face her. "I try to, whenever I have time. I do a few laps around Central Park. 15 miles or so."

Claire laughed. Natasha didn't. Claire's laughter trailed off. "Oh. You're not joking. Goddamn. And here I thought I had a decent mile time."

The corner of her mouth quirked up. "You run, too?"

"Yeah, I—"

Suddenly, the elevator shuddered and came to a stop. Claire's muscles tensed, expecting the worst. Was it a tech issue? She looked around the elevator frantically for something that might tell her what was wrong. The floor numbers stopped climbing. The lights flashed once, twice, then powered off completely.

"Shit," Claire muttered.

They were trapped.