Note: I combined two prompts for this first story.

Characters: Sherlock & John

POV: John

Prompt 1: Sherlock passes out from pushing himself too hard for a case.

Prompt 2: Sherlock once lost a case. He caught the murderer, but not before someone else died, and he regrets that terribly.

Submitted by: Arowen13

"This kind of wound doesn't happen in self-defence. It's deep, deliberate… but the knife couldn't have been more than four inches long, which means the attacker would have had to get in close. He knew whomever killed him - knew him intimately. Look at his hands, Lestrade. Those aren't defensive wounds, they're scrapes from when he fell to the pavement."

John isn't really listening as Sherlock paints a lurid murder scene on a cool September afternoon. He's standing beside him as they consult with Lestrade over a conference table covered in photographs and notes. Sherlock is rehashing, starting again from the beginning to try to find whatever it is he's missed. They've been on this case for ages with no leads and barely anything to go on. John doesn't even see the gruesome details in the photographs anymore, doesn't process them. They've become background noise at this point; just a sad, unavoidable fact of the case.

Normally, crimes get solved in record time with Sherlock on the case. This time, though, it's been four weeks and two dead ends and they are hardly closer to the solution than they were a month ago. Sometimes, John thinks they might even be going backwards instead of forwards.

But it isn't the case John is worried about. Not today, not now; not when he can see, even under the bleaching fluorescents of New Scotland Yard, that his flatmate's strength is waning. For weeks now, John's pleas to eat, drink, and sleep have only been heeded to the barest extent. Sherlock obeys only when he has no other choice. The stress of the case isn't helping, either. This murderer has eluded Sherlock for far too long, and that bothers him. Bother is too mild a word, though, John knows. It's more than that. Sherlock finds it deplorable, disgusting… unthinkable, that his great mind can't find a killer who was careless enough to leave his one and only victim out in broad daylight. The challenge was refreshing at first, John knows, but now it's gone on too long and Sherlock is sick of playing. He plays to win, after all. Right now, he's not winning.

"We've interviewed everyone associated with the victim," Lestrade is saying now, shaking his head. "He can't have known the killer, unless it was a big secret."

"What about Michael Camden?" Sherlock presses. "He ran when we questioned him. Remember?" He looks to John for support.

John nods, recalling with clarity the rooftop jaunt in Southwark.

"You said he ran because of the warrant out for his arrest," says Greg. "He didn't know anything when we questioned him, anyway. Now he's serving time for robbery."

"I need to speak to him again."

Lestrade's pager goes off and he pulls it off his belt to glance at the display. He heaves a sigh. "I've gotta go. I'll arrange an interview with Camden." He strides to the door and holds it open for the other two, waving them through. "Don't do anything without me, though, Sherlock. The press are watching this one like hawks."

Sherlock doesn't say anything, but his lack of argument passes for agreement, and John follows him out.

221B is dim and quiet and warm when they return some twenty minutes later. Mrs. Hudson comes up bearing a tray loaded with tea, sandwiches, and biscuits just after they boys arrive home. "Hungry?" she chirps cheerily.

"Yes," John says eagerly.

At the same time, Sherlock says, "No."

Mrs. Hudson tut-tuts and bustles out, and John gives his flatmate a reproving look. "Sherlock, you need to eat," he says for what feels like the millionth time in two weeks.

"And suppose someone else dies while we're eating biscuits," the detective snaps with unwarranted aggression. He shrugs out of his suit jacket and turns his back to John, staring at the mess of notes and photographs tacked to the wall. "Let your sentimentality deal with that."

The next day is the same. They're visiting the crime scene again. Sherlock is restless, agitated. They've combed the scene half a dozen times already. There's nothing new here and he knows it, but lives are at stake and more importantly - the game is on and Sherlock is losing it.

John can smell rain as his flatmate walks the perimeter of the area. The body was found in a park. That section of the park is still roped off from the general public, at Sherlock's request, though certainly some kids have sneaked in a few times for a laugh.

"If he thinks he's gotten away with it, he may kill again," Sherlock says as he comes to a stop in front of the park bench where the body had been posed.

"On the other hand, he may not," says John, irritably.

Audibly, Sherlock exhales. He doesn't say anything. He's swaying.

John grabs him under the arm and hauls him away. His lack of argument is more worrying than anything else.

Another day, Sherlock is staring at a computer at the Yard when his eyes go glassy. John is poring over a new case file that may or may not be linked to their murderer, but he's doing it in spurts and jags because his eyes are continually drawn to his flatmate, who is pale and silent and stony - more so than usual.

Without warning, Sherlock sighs and slumps and cradles his head in his hands.

"Sherlock?"

The detective doesn't answer.

"Sherlock," John says again, more insistently. He reaches across the table and pokes an arm.

"I'm fine."

"Take a break."

"I'm fine." His phone rings. It's sitting on a table across the room. "Get that."

They're at home when it finally happens, two days later. John has been expecting it for some time, but that doesn't make it any less alarming in the moment.

Sherlock is carrying a thick reference book in from his bedroom, but suddenly drops it with a resounding thump onto the floor. John looks up in time to see him list to one side and grab the back of a chair for support. "Sherlock!"

The detective's voice is faint and he's frowning. "John…" His knees buckle and the hand that was holding him up goes slack.

John leaps to his feet and crosses the room in two strides, but Sherlock is on the floor before he can get there. The sound of his limp body hitting the hardwood makes John's stomach churn uncomfortably, and he cringes as he drops to his knees beside the detective. Sherlock is lying on his back in a heap, his face partially obscured by a shock of dark curls. John's fingers immediately dig for a pulse in his throat, though he knows full well that Sherlock is fine; but the strong, steady beat beneath his fingertips calms him. He pushes his flatmate onto his side, flicks open the top two buttons of Sherlock's shirt, and yanks his own jumper off over his head, folding it under Sherlock's head. By the time he does this, Sherlock's eyes have opened, grey-green scanning John from folded knees up until they find his face.

"Sherlock?" John says softly, mindful of any headache that may be developing, from the crash to the floor or otherwise.

"John?"

"You're okay. Can you sit up?"

Sherlock doesn't speak, but appears to be considering this. After a few moments, he blinks fiercely and begins pushing himself upright. John helps him sit up with a hand at his back, watching for the colour to drain from his face and signal that he's going to pass out again. As expected, Sherlock does look a little white once he's straightened up, and he groans and presses a hand to the side of his head.

John immediately pushes Sherlock forward with a guiding hand on the back of his neck, forcing him to put his head between his knees. "You're alright," he repeats. "Breathe."

He does, slowly and deeply through parted lips, pressing the heels of his hands into his eyes.

Leaving him to it, John climbs to his feet and goes to the kitchen to fill a glass with water. Sherlock will probably balk, he knows, at being babied, but quite frankly, John has had more than enough of this. He'll have Lestrade dump him off the case if he has to. Steeling himself, John returns to where his flatmate is still sitting on the floor, cross-legged now with his back slightly bent as he stares at his ankles. John squats down beside him and holds out the water glass.

Something in Sherlock's throat thrums deeply - gratefully? - and he accepts the glass, sipping cautiously.

"How are you feeling?" John risks asking. He ducks his head a little to peer into his patient's eyes.

Sherlock draws back a little from the scrutiny, frowning openly back at John. At first he doesn't answer and drinks water instead, but after a moment he sets the glass down and scrubs a hand across his forehead. "I'm fine."

"Don't say that," John snaps. "You haven't slept in days. You barely eat enough to function. You haven't said two words that don't have to do with the case in I-don't-know-how-long. This has to stop."

"You know I don't do those things when I'm working."

"And I know it's worse this time. What I don't know is why. But it doesn't matter. Sherlock, I draw the line when you knock yourself out on my living room floor."

Sherlock blinks owlishly back at him, possibly cowed by the reprimand and definitely surprised by it. He is usually the one giving orders around here.

John is acutely aware of the fact that he has never spoken to Sherlock in this tone of voice before, not like this. Perhaps he's shouted at him once or twice about minding his Ps and Qs around other people, but nothing like this. His tone during this conversation has been sharp and commanding - his 'Captain Watson voice' is what Lestrade has called it in the past. Usually reserved for criminals and uncooperative witnesses, and once for getting in and out of Baskerville. This is different. This is personal, intimate. His stony expression doesn't slip as he asks, "Can you stand?"

The detective finishes his water and doesn't answer. Instead, he pushes himself to his feet under his own power, only listing slightly when he's gotten himself to his full height. He shakes off the hand John extends and steadies himself instead on the chairback. "The longer we delay, the more of a threat this man poses to everyone around him."

"Scotland Yard is on the case. You need to sleep, Sherlock, the work can wait for eight hours while you do that. Hell, rest might even help you solve the case, you know. Sleep deprivation seriously inhibits brain function."

"Every minute counts, John," replies Sherlock, shaking his head, even though he is holding onto the chairback with two white-knuckled hands now. "At any moment - "

John cuts him off. "Since when do you care about human life?" he cries before he can stop himself. "As long as you solve the case, you win, you can't take a night off to - "

"Since Natalia Novak."

"What?"

"Natalia Novak," Sherlock says on a sigh. Defeated, he pulls the chair out and drops down into it. He sets the water glass down on the table and studies his reflection.

"Who's Natalia Novak?" John demands curtly.

"It was a long time ago. Before you. It was… I lost. Sort of." Sherlock's face contorts uncomfortably for half a second. "I solved the case, but not quickly enough. Adrian Miller killed an American tourist by the name of Emily Duncan, a year after I started consulting with the Yard. He was clever about it, though. He cleaned up after himself. There wasn't much DNA evidence at all, and what was there wasn't in the database because he didn't have a criminal record and had never been bonded or fingerprinted. He essentially disappeared after he killed her. Hence why Lestrade needed me on the case. I took too long tracking Miller down, and less than a day before I found him, he killed another tourist called Natalia Novak. If I had just gotten to him a few hours sooner, I could have prevented that."

Now it is John's turn to be cowed by his flatmate's words. He is ashamed of himself - ashamed that it took him so long to ask, and ashamed of the way in which he eventually did. He releases a breath he didn't realise he's been holding and sits down heavily in an adjacent chair. "Christ. How long between the killings?"

"Six weeks."

That answer isn't surprising. Sherlock has had his head in a case from five years ago all this time - as far as he was concerned, he had a six-week window at maximum to find a suspect. No wonder his condition has spiralled out of control as time went by, especially in the last few days. It's been almost five weeks now; the timer is running out of sand. "I'm sorry," John manages.

Sherlock shrugs.

They sit in silence for a few moments, John watching Sherlock and Sherlock watching his water glass. Finally, John scrapes together his resolve and clears his throat. "Still - you need rest, and food, and water, for God's sake. I know you don't do those things while you're working," John says quickly before Sherlock can interrupt, "but when a case drags on this long, you have to."

For a long time, Sherlock doesn't answer. He's scowling at his water glass now, no doubt irritated with his transport for having needs that interfere with his all-important work. But finally he says, in a small voice, "It would seem so."

John thinks that this is agreeable enough. Then something else occurs to him. "Listen, um… you know it wasn't your fault, right?"

"What?"

"Natalia Novak."

Sherlock's face goes through several changes very quickly. John thinks one of them is surprise, another relief, but the rest are unreadable. He settles, in the end, on feigned indignance. "Don't be an idiot, John."

Okay, John thinks to himself, but he decides not to say anything. He watches Sherlock stand up, the chair scraping back as he does. He tenses. "Where are you going?"

"Bed," the detective replies.

John is surprised - pleasantly so - but he doesn't push his luck by questioning it. "Goodnight."

"Goodnight."