Grissom almost sloped past the room, when a glimpse of the slender brunette stopped him in his tracks.

"Hey, there you are." He frowned, shuffling into the dimly lit lab.

"Here I am." She agreed apathetically, not bothering to tear her gaze from her work.

He paused for a moment, shaking his head at her cool response, before joining her at the bench.

"Do you have the Johnson case file? I can't find it with the evidence."

Sara straightened up, pursing her lips.

"Yes, I do." She nodded slowly. "I just don't know where it is."

His perplexed expression deepened.

"You don't know where it is?" He echoed.

"It's in the lab, somewhere." She corrected herself quickly. "I just can't remember where I put it."

For a moment, he studied her sheepish expression, before offering a meek shrug.

"Okay. Well, when you find it, let me know."

She blinked, surprised by his lack of concern. She had expected a lecture about carelessness; or at the very least a little-known quote from Tsung Tzu or the like.

"Sure." She agreed cautiously. He started to walk away, but came to an abrupt stop in the doorway and turned back to face her.

"Are you okay? You seem ... tired." He decided, taking a moment to choose the right word.

She planted a smile on her face, attempting to force herself to relax despite every aching muscle in her body screaming at her to stop.

"Yeah, I'm fine. I've just got a lot on at the moment."

For a gut-wrenching moment, she thought he was going to keep pushing; but he offered up nothing more than a small nod of acceptance, and then he was gone.

Sara exhaled, taking a few seconds to bask in the relief of having bought herself some time. Sure, she had battled to get Grissom's attention in the past; but every now and then it worked in her favour that he was so utterly oblivious to human emotions.

She had never been so relieved to hear the gentle click as the key worked through the gears and unlocked the door. Stepping into the apartment, she shut it behind her and immediately locked it again. It was second nature to do so – a side-effect of living in a city like Vegas – but she found herself checking that it was definitely secure, just in case. She had done the same with her car and her locker at work.

Satisfied that the door wouldn't budge, she moved further into her home and tossed her keys onto the bench – also second nature. However, instead of clattering onto the marble-effect counter, they landed with a gentle thud onto a cardboard folder.

Sara stilled, staring wide-eyed at the file. It was just sitting innocuously on the edge of her counter; but it hadn't been there when she'd left for work several hours ago. She knew it hadn't been.

Sliding her keys off it, she opened it just enough to see the name written on the first page; although in the pit of her stomach, she already knew what it said.

She stopped just outside the door, cocking her head to the side. She could see through the glass walls that Sara was alone in the break room, and yet she could hear the young woman muttering, apparently to no one in particular.

"Hey." She greeted cautiously, stepping inside. Sara visibly started, barely managing to keep hold of her coffee mug. Catherine sent her a concerned look. "Are you okay?"

"Yeah, why wouldn't I be?" Sara cleared her throat, attempting to compose herself as she took a seat at the centre bench.

"Well, you're like a cat on hot coals, for one thing." Catherine noted with a tiny smile. "And you're talking to yourself, for another."

Sara shot her a dismissive look.

"I am not talking to myself. I'm just trying to work something out."

"Out loud." Cath added pointedly, joining the brunette at the counter.

Sara set her gaze straight ahead and made a point of drinking her coffee without acknowledging the comment.

"Gil mentioned that you seemed kind of off yesterday." The older woman continued, trying to study her colleague's features. "Is everything alright?"

"Everything's fine." Sara fought the urge to roll her eyes, sensing that it would not go down too well with the persistent supervisor.

She could still feel Catherine's pensive blue eyes watching her, but refused to meet her eye, lest her guarded mask start to slip.

"Alright then." The blonde said at last, although it was clear from her tone that the conversation was not over yet. She remained sat beside Sara, the two of them silently waiting each other out for several minutes, before the young CSI finally relented. Wordlessly, she slid a plain manila folder across the bench towards Catherine.

"What's this?"

"It's the Johnson file." Sara explained calmly.

"Oh, you found it."

"Yeah." She nodded, cupping her hands around her coffee mug to stop them from fidgeting. "At home."

Catherine looked up, beginning to realise why her colleague appeared on edge.

"I thought you lost it in the lab?"

"I did." Sara turned to her, the faintest hint of fear starting to creep through her poker-face. "You're a scientist, Catherine. Explain to me how I could have lost it here and yet it somehow found its way into my apartment."

"Are you suggesting that someone else put it there?" Catherine raised her eyebrows sceptically. Sara sat forward, resting her head on her hands, and sighed.

"When I got home yesterday, my front door was unlocked."

"What?"

The exclamation came out more dramatically than she intended and Sara jumped in her seat.

"There was nobody there, but the door was definitely unlocked and I know I locked it before I left."

"Was anything missing?" Cath pressed, feeling her heart rate increasing, though she couldn't entirely explain the sudden feeling of panic.

"No."

"Are you sure?"

"Catherine, I'm sure." Sara insisted, swallowing around the lump in her throat. "I checked everything and nothing was missing. But that was sitting on my kitchen counter when I got home this morning."

"Have you filed a report?"

"And say what?" Sara laughed bitterly. "That someone broke into my apartment and left me the thing I'd been looking for all day?"

"Alright." The older woman nodded, understanding her reluctance. It did sound strange, even to her. "Well, is there anyone else who has a key?"

"Nick has a spare key, but unless he's deliberately trying to gaslight me, I don't think it was him."

"No, perhaps not." Cath pursed her lips. "What about Belinda?"

"No, she never had a key to my place. And anyway, when would she have been able to get the folder?"

"She does still work here sometimes; she could have taken it when you weren't looking?"

"I don't know." Sara frowned, her sinking her teeth into her lower lip in contemplation. "I can't see her pulling a stunt like this just to screw with me."

Catherine opened her mouth to contest the matter, but the entrance of Grissom and the boys brought the conversation to an abrupt end.

"Hey Sara!" Nick greeted cheerily, his joy at seeing her written all over his face. Since the team had been split in two, he had missed their casual flirting and friendly insults.

"Oh Sara," Grissom glanced up briefly from the case file he was nose-deep in. "I gather that you know you're with Catherine's team tonight?"

Sara turned to face her companion, one eyebrow arching in question. Cath flashed her a sweet smile. If Sara had thought that she was going to escape the discussion anytime soon, she was sorely mistaken.

"Sorry, did I forget to mention that?"

Jim Brass was not a man of many words, and even fewer when there were dead bodies to deal with.

"Husband and wife, looks like it could be a domestic gone wrong. The husband's in the kitchen, the wife in the living room. Neighbours heard gunshots about an hour ago." He rattled off in a clipped voice.

"Alright." Cath nodded, surveying the scene. "Sara, why don't you take the perimeter and work your way into the kitchen from the back garden. Warrick, you take the upstairs and work down to the living room. Start in the bedroom."

"You got it, boss." The dark-skinned CSI handed Sara her kit from the back of the car and the two of them set off on their respective tasks. Warrick knew that Nick had been disappointed not to be working with Sara; but he was glad of the opportunity himself. Not in the least because he had been trying to catch her alone for a while. They may not be on the same team anymore, but they still worked in the same building and her change in demeanour of late had not gone unnoticed by the astute CSI.

But this was neither the time nor the place to discuss it, so he handed her the metal case without a word and made his way into the house.

Since there was not much of a front garden to speak of, and most of it had already been trampled by police officers and paramedics, Sara opted to go straight to the back garden via the narrow strip of grass running alongside the house.

"Alright, what do we know about our victims?" Cath asked of Brass, using the time to scan the house and neighbourhood while he recited what he had already learned.

"Married six years, he's a stockbroker, she's a dental assistant. They moved here right after they got married. No kids. Apart from a couple of drunken domestics a few years ago, neighbours said they were a quiet couple."

"Nice area." Cath noted, casting a glance over the shell-shocked faces of the neighbours. "I bet most of these people have never heard a gunshot before, never mind in their own street."

As if to prove her point, the gathering crowd suddenly emitted a frightened shriek. Men dived for their wives and children, police officers ducked low to the ground and drew their weapons, with barking hurried messages into their radios.

But Catherine didn't hear any of that. All she heard was the deep echo of the gunshot that had just rung out from the back garden.