The hallway was filled with swirling grey smoke. It danced around them, almost as if it were actually alive, as they stumbled blindly down the corridor.

Sara felt Greg's hands guiding her through the maze of labs, using his body to shield her as much as possible; although what he was protecting her against was anyone's guess since they couldn't begin to locate the source of the obstructive smoke.

Finally, they spotted a few stragglers heading for the front doors and spilled outside alongside them. The first gulp of fresh air was bitterly cold against their burning lungs.

"Oh, thank God." Grissom breathed, rushing over to his two missing team members. "Are you guys alright?"

Sara and Greg gave each other a quick once over and nodded breathlessly.

"Yeah, we're fine." Greg coughed. "What's going on?"

"We don't know." The aging man rubbed a hand through his short hair. "The fire alarm alerted us to the smoke, but it spread so quickly we couldn't work out where it was coming from."

They nodded along, although they had only actually caught the first half of his sentence as the emergent fire sirens drowned out the rest.

The boss hurriedly ushered them both down the steps towards the rest of the team, who were huddled together in a sheltered part of the parking lot.

Since none of them were dressed appropriately for outside weather, Nick was hopping from one foot to the other in an effort to keep warm and Catherine had practically fused herself to Warrick's body. She smiled in relief when she saw Sara approach and reached out to pull the brunette into their little circle. Warrick absently wrapped an arm around each woman, pulling them tighter against his chest as he watched the newly-arrived firemen dash into the building.

Across the parking lot, two figures strolled towards the gathered group, eyeing the excitement with unbridled curiosity.

"What happened, Nicky? One of your experiments go wrong?" Brass teased playfully, earning a half-hearted smile from the Texan.

"We heard on the police scanner." Sofia interjected, more serious than her Captain. "What's going on?"

"We don't know." Grissom shrugged, spotting another person in the amassed crowd. "Excuse me."

He trotted off to collar Ecklie, who was currently rather busy harassing the fire chief for some answers of his own.

"Man, this is going to be expensive." Warrick whistled, noting the expanse of smoke that billowed out of the swinging front doors.

"I don't know." Greg frowned. "This doesn't feel like a fire – there isn't any heat, just smoke."

"You're right." Sofia hummed in agreement, casting her eyes over Sara. The brunette was staring resolutely at the building, whether in shock of just to avoid catching anyone's eyes she didn't know.

As it happened, the detective had been on her way to CSI anyway when the alert came in. She had been reviewing her conversation with Kirsty Soames the other night and she wanted to clear some things up with her ex.

She hadn't actually meant to say it, it had just slipped out. The cop didn't seem too offended by her confession, more shocked than anything. But that wasn't what was concerning her.

In her sudden guilt at having just outed both herself and Sara, she had forgotten to ask how Kirsty even knew Sara. And for some reason, the thought simply wouldn't leave her alone.

X x x

"Smoke bomb." The chief declared, scratching his head beneath his helmet.

"A single smoke bomb did all that?" Catherine asked sceptically, thrusting herself off the doorframe and joining them at the centre bench.

"Yep." He insisted gruffly. He was a large man – in every dimension – with thinning grey hair and a rough complexion to match his voice. With his fingers hooked into his suspenders, he could almost pass for a character out of a black and white comedy sketch.

"This was one powerful smoke bomb." He continued, releasing a snort. "Lucky it wasn't a stink bomb, you'd have had to vacate the building for a week!"

Ecklie scowled, not in the mood for his crass jokes right now.

"When will we be able to get the lab up and running again?" The director asked, straight to the point.

"As soon as my guys have checked that there's no damage to the equipment. I wouldn't worry though, it should be fine." The man assured them. "All I can tell you so far is that it started outside your changing room."

"Who set it off?" Grissom asked absently, talking to himself more than anyone else. "And why?"

"That's your job." The fire chief grunted again, clearly not familiar with Grissom's vacant moods.

"We'll have to do a full inventory of evidence, see if anything was taken." Catherine changed the subject. "If anything is missing then it could point to motive."

Ecklie released a heavy sigh.

"Yeah." He agreed despondently. "Alright Catherine, you take Sara and Warrick and get onto that. Get the lab techs to help you." He instructed, gesturing across the hall to the mass of people in lab coats picking over their smoke-covered evidence despondantly. "Greg and Archie can check the CCTV footage and Nick can help Grissom examine the bomb."

Cath nodded, quirking an eyebrow at the man. "What are you going to do?"

He sighed again, sending her a forlorn look.

"I'm going to go explain to the Sherriff why he has to have his lab deep cleaned for smoke damage."

Sharing a small smile at his misfortune, Cath and Gil locked eyes across the room.

"I guess I'll go grab the guys." She said at last.

"Hey Cath," he called after her. "See if Sofia will help too. The sooner we get through this, the sooner we can get back to normal."

She nodded, slipping out in search of her team.

"So," Brass hummed, pushing himself off the back wall. "Where do you need me?"

Gil smiled, a look that could only mean bad things for his old friend.

"The morgue." He said cheerfully. "You're going to help Doc Robbins and David check that all of the bodies are still where they should be."

X x x

Seeing as it was the source of the smoke-bomb, Sara wasn't even sure she was meant to be in here; but no one had stopped her so far.

She swung her locker open, her brow furrowing at the sight of a small metal box sat innocently on the shelf.

Using her sleeves to cover her hands, she lifted it out and carefully prised the lid open.

The smell hit her instantly. It was almost familiar, but she couldn't quite place it.

Scrunching her nose up, she blinked at the contents in a mix of confusion and shock.

Like before, someone had left only one word on the note. The same four angry letters as before stared up at her in silent abuse.

Only this time it wasn't just a harmless piece of paper. This time, whoever had left the vile message seemed to be trying to get at her twice over.

They had written it onto a piece of beef jerky.

On instinct, she hurled it away from her body. It clattered into the trash can, the metal lid of the box slamming shut as it pin-balled its way to the bottom.

Bracing herself against the lockers, she released several deep breaths, trying to regain some sort of composure. Who the hell was doing this? And why?

"Sara?" The voice startled her and she jumped to face the door, guilt written all over her features at being caught out.

Sofia frowned, picking up on her ex's obvious discomfort.

"You okay?" She asked, coming further into the room.

"Yeah, I'm fine." Sara breathed, running a hand through her hair. "It's just … you know, hectic night."

"Yeah." Sofia smiled sympathetically. "Catherine's looking for you."

"She is?" Sofia obviously noticed the tremor to her voice, but elected not to call her on it. Yet.

"Yeah, she wants us to do inventory on all the evidence in storage; make sure nothing's missing."

"Right, okay." Sara nodded, slamming her locker shut and and following the blonde back into the hallway. She paused in the doorway, casting a nervous glance back at the trashcan.

Something told her that she had just found the reason for the smoke bomb.

But why would someone go to so much effort just to upset her?

X x x

"Alright." Catherine planted her hands on the table. "Archie and Greg are sorting AV, so; Mandy, you take Warrick and do fingerprints. Sara, you go with Wendy, Sofia take Henry. David," she flashed Hodges a false grin, "you're with me."

"Oh goody." He replied, mock sarcastically.

"What about Bobby?" Sara asked, noting the ballistics tech busying himself in his lab as they were speaking.

"He's checking all of the weapons are secure first." Cath explained. "Whoever finishes first, you get Bobby."

"Awesome." Warrick nodded. "Let's get this over with."

"What, you don't want to spend the night with me?" Mandy teased, following him across the hall.

As they each dispersed, Sara tried to leave but found herself trapped, face to face with Sofia in the threshold.

"Hey," the detective cleared her throat. "Can we talk?" She asked in a low, conspiratorial voice. "There's something I need to tell you."

"I can't." Sara attempted to side-step her but found herself pinned between the woman and the doorframe.

"Please." Sofia pressed. "It'll only take a few minutes."

Sara cast an anxious glance into the DNA lab, where Wendy was waiting patiently for her to follow.

"Alright," she conceded reluctantly when it was obvious that she wasn't leaving until she agreed. "Just, not now, okay?"

Deciding that that was as good as she was going to get, Sofia stepped aside and let her escape.

In truth, it was probably best left until later anyway. That way she could work out what she was actually going to say.

However she spun it, Sara wouldn't like what she had to say.