A/N: Thanks to my wonderful betas, Koohii Kappu from Psychfic and zenaxina for all of their help!

Standard disclaimers apply.

Around noon was when things went straight down the toilet.

Literally.

Or, rather, it would have been literally if there had been a bathroom nearby. In this case, it turned out to just be all over the floor in a hot, abandoned warehouse.

Unless he was actively dying, the Head Detective's response to the occasional physical interference was to pop whatever over the counter medication was most appropriate, wash it down with a mug of strong coffee, and go on about his day. Looking back, he would be hard-pressed to pinpoint exactly when it had started.

Rewind…

7:30 that morning was when the first indication something was wrong cropped up. (Admittedly, it may have started earlier, and he'd just ignored it.) His morning was off to a quiet start, for which he was grateful after several solid days of back-to-back cases that had kept him at the station late, and he was taking full advantage of it to address a stack of long-overdue paperwork. Halfway through, the grumbling started somewhere deep in his gut as a low pounding registered in the back of his head. It was too insistent to brush away, so he washed two aspirin down with a cup of coffee and went back to typing.

An hour later, his phone rang. Body in an alley behind a coffee shop. No immediate cause of death. Found by a dishwasher taking out the trash after the breakfast rush. Easy enough. Lassiter could be there in ten minutes if rush hour traffic heeded his siren.

"O'Hara!" he called to his partner as he hung up the phone, stood, and grabbed his blazer ago in the same motion. "We caught a case."

Then it was off into the morning sun, their shoes clipping against the asphalt as they hurried for the car. The partners slipped into their long-practiced routine of reviewing any details they had while heading for the scene, but then O'Hara paused and frowned across at Lassiter.

"What?" he asked, confused when she stopped mid-sentence.

"Carlton, are you okay?" She sounded concerned. "You look kind of pale."

He shook his head dismissively. "I'm fine. Don't worry about it."

Although she didn't seem completely convinced, she didn't push the issue further.

The next six hours would make the day one for the books.

McNab was already at the scene, and he was more than ready to recite the facts of the case as soon as his superiors came up alongside him. Listening to the officer's account, Lassiter found it oddly hard to focus on the taller man's face. The sun, he decided, was the culprit. It was behind McNab, which put it right in Lassiter's line of sight. That would explain the way the detective's vision was blurring ever so slightly and his head pounding more than before… plus it was suddenly uncomfortably warm, which was another reason Lassiter preferred not to stand around dawdling when there was work to be done.

But before he could ask any questions, a very familiar (and very unwelcome) voice met his ears. Lassiter did not have time for this; he turned on his heel to face the intrusion head-on. "Fantastic, Spencer," Lassiter snapped, responding to the other man's words without actually acknowledging them (it was a skill he'd perfected, and he was proud of it), "but we do not need you out here chasing ghosts."

"Not ghosts, Lassie. That would be silly. Ghosts can't do this." Spencer shook his head. "Not even that creepy phantom guy on that boring musical Gus likes so much. This is no case of a falling chandelier. No! A crime of passion it may be, but there is something much more human at play in this crime scene!" Then he grinned, as if extremely happy with himself.

Funny, he'd often made the hyperbolic complaint that Spencer made him sick to his stomach, but this time, the "psychic" seemed to have actually succeeded at doing so. Somehow, that surprised Lassiter more than he'd expected. Swallowing against the faint hint of bile rising in the back of his throat, Lassiter rolled his eyes. "Spencer, I didn't call you. We don't need your help. Get out."

Never one to be easily dissuaded, Spencer continued grinning. "Sure you do, Lassiefrass. Otherwise, you'd categorize this as a simple mugging and leave this poor, poor man without true justice."

"What are you talking about?" the Head Detective snapped. He wasn't about to admit he'd mentally cataloged the scene as a mugging within five minutes of arriving. Between McNab's summary and the evidence Lassiter had already taken in, his working hypothesis was that the victim had ended up in the alley after an assailant had stabbed him, dragged him into the alley where the SBPD was currently gathered, then relieved him of wallet and watch.

Lassiter wasn't quite sure what happened in the next minute, but suddenly Spencer was yelling something along the lines of "He did it!" and "Don't let him get away, Lassie!" and pointing at a fleeing figure. As soon as Lassiter had glanced over, Spencer spun and ran in the same direction as the fugitive.

The man now on the run had been part of the crowd of lookie-loos gathered on the other side of the crime scene tape, and Lassiter growled in his throat as he took off after the others.

He noted in surprise that his knees felt weak as he pushed off from the pavement to give chase. It was worse than that time O'Hara had somehow convinced him to run the SBPD Half Marathon with her, but he didn't have time to contemplate his body's strange behavior. He had a murderer to catch, so Lassiter pushed everything else aside and raced forward. He heard footsteps behind him and turned to see McNab following close behind. That was good. Not that Lassiter couldn't handle things on his own, but backup was always a good thing to have, regardless of the situation.

Fast forward…

In a twist that no one (not even Spencer) had seen coming, the chase had somehow wound through an old warehouse. And then even more surprisingly, the fugitive had disappeared once inside.

Spencer had also seemingly vanished (although Lassiter couldn't have cared less), so Lassiter and McNab had spread out to search carefully behind these random stacks of crates piled around the floor. There were also several offices along a catwalk that served as a partial second floor, and Lassiter moved to clear them.

And that was when everything that had been compounding all day came to a head.

It must have been something about the sudden change in altitude because nausea suddenly hit him like a tidal wave. He couldn't ignore it now, nor could he push aside the roaring in his ears nor his pounding headache.

He staggered and would've fallen back down the three stairs he'd managed to mount, but a strong pair of hands caught him from behind and helped him ease down to a sitting position.

"Sir? Detective Lassiter, are you all right?" That was McNab's worried voice, much too loud and close to Lassiter's face for comfort.

The Head Detective grunted and forced his eyes open. He wanted to lecture the younger officer, but he only got as far as, "McNab—" before his stomach asserted itself.

Lassiter leaned to the side, something in his thought process telling him it would be a very bad idea to vomit all over McNab, and just managed to clear the other man.

McNab made a face that he quickly covered up when Lassiter looked back to him. "Sir, are you all right?"

Of course he wasn't all right. Was McNab kidding?

But again, his words failed him, so he just glared in response.

Lassiter really had no idea what was happening. His first thought was that he'd been poisoned, but then he mentally ran through his schedule over the past two days and found himself at a loss to explain when someone would have had a chance to do anything to him. He'd been so busy with his caseload that he'd barely even stopped for meals. Sure, he'd eaten takeout, but he and O'Hara had split orders each time, and she'd seemed as chipper as ever that morning (in contrast to the way Lassiter had felt—even if he'd tried to ignore it). Besides that, he'd had station coffee and a couple of protein bars, and there was no way anyone had tampered with those…

And then his thought process was interrupted by more churning deep in his stomach. He swallowed hard, hoping to contain it, but the effort was in vain. He could feel the bile as it tracked upward, and he knew what was coming, but he barely had a chance to anticipate it before it forced its way out.

He'd only had coffee and some water that morning, and he already lost that in the first round, so there wasn't much left. So this time, he finds himself dry-heaving, which in turn leaves him gasping for air between rounds of his stomach wringing itself dry.

If not for McNab quickly moving to his left side and grabbing his shoulder, Lassiter would probably have pitched headfirst off his seat. Thankfully, the other man was there and prevented disaster. Lassiter grinned in thanks, although it was more of a grimace than an actual smile.

For his part, the officer looked extremely concerned. "Sir, are you sure you're all right? I really think we should get you to a hospital," he said.

Lassiter had to agree. As much as he hated the idea of a hospital stay of any length, it was starting to look like his only real option at this point. There was a 99% chance that he would not be able to go back to the office and have a normal workday—and not just because O'Hara and McNab would never let him. Lassiter was actually not sure he would physically be able to make it to the end of the day. That was not something he was used to having to admit to himself, and it was a weird thought.

Then, before he had a chance to think things through any further, his stomach twisted again, and he was yet again leaning over and heaving.

When things calmed down, Lassiter wiped his mouth with the backside of his hand and gave McNab a long look. "You need to go get help," he said.

McNab shook his head. "No, sir. I'm not leaving you like this."

"Well, can you at least call for help?" Lassiter grunted. He wasn't sure why he hadn't led with that question, but better late than never he supposed.

Again, the other man shook his head. "I tried," he offered. "But there is no service here for some reason." He grinned hopefully. "But I'm sure Detective O'Hara will come looking before too long. And Shawn has to be around here somewhere, right?"

The other man's naivety might be amusing under other circumstances, but right now, Lassiter did not have time for this. "McNab," he said, "I'll be fine… go get someone."

He didn't look sure, but after a moment, McNab nodded. "Okay," he acknowledged. "But at least sit down here on the ground, sir." He helped Lassiter to the indicated position below where the Head Detective had been sitting on the stairs.

Lassiter supposed that was a smart idea. He had already almost fallen down the flight of steps several times. If the officer was not there to catch him, Lassiter wasn't quite sure he would be able to catch himself in time.

It seemed like he had only blinked, but suddenly he was alone in the warehouse. On a normal day, it wouldn't have bothered him in the least. However, nothing that had happened so far that day was anywhere close to normal.

With a sigh, Lassiter closed his eyes and leaned back, resting his head on the metal handrail where it met the floor. If he just closed his eyes for a few minutes, maybe everything would reset itself. He wondered what the chances were that this was all just a terrible dream and he would soon wake up in his own bed to the sound of his alarm.

He briefly considered pushing to his feet and forcing himself to follow in the direction McNab had disappeared, but then he took in how weak and shaky he was starting to feel, and he quickly vetoed that idea. He didn't know what was going on, but none of his extremities seemed to want to heed his brain's instructions. It was a weird sensation, and he wasn't quite sure what to do with it. Maybe if he just rested a few more minutes…

A sudden clang from off to the side snapped his eyes open and had his full attention. Lassiter blinked a few times, trying to bring his surroundings into focus. Everything seemed to be swimming around him in a blur of colors, and he had to admit that his head was pounding so hard it felt like it was about to explode.

"I've called for an ambulance." That was O'Hara's voice, and she sounded worried.

McNab now. "They should be here soon, right?"

The voices continued, but it was too difficult to follow the conversation. Lassiter's head was still swimming, and if he thought about anything for too long, his stomach started roiling again. The last thing he wanted or needed at the moment was to puke again, so he did everything in his power not to focus too hard.

However, in the next moment, he realized he maybe should have been paying attention. Without any further ado, someone's arms slid underneath his bent knees and another arm curled around to support his back. Lassiter barely had time to realize it must be McNab before he felt himself rising from the ground.

It was embarrassing how limp he felt himself going, and it took almost all of his remaining strength to crack an eye open to confirm his theory. The other man looked extremely serious and concerned all at once, but Lassiter didn't have much time to dwell on it before he felt himself drifting away as they continued to wherever their destination would be...

It was sometime later that afternoon before things returned to normal. Or at least, as normal as they could be when Lassiter was being forced to take up residence in a hospital bed and Spencer had been the one to apprehend a fleeing murderer.

He had an IV in his left hand that was pumping him full of fluids, and his head felt remarkably better than it had back in the warehouse. His partner was sitting in a chair next to his bed, and McNab had only recently disappeared with the promise that he would be back soon.

The doctor had diagnosed the head detective with a severe case of food poisoning but had promised that, with rest and the right treatment, he would make a full recovery. That was good news as far as Lassiter was concerned, although he was less than enthused to hear that he needed to take a few days off to fully recover. When he felt up to it, he would probably argue the point, but for now, he was content enough to lie back against the pillows (and not be throwing up).

Fin.