Sherlock is lost.
Earlier that morning, he had watched his best friend shuffle into the flat after a 12-hour shift at the clinic, looking even worse than when he had fallen into the Thames during their last case. By the looks of it, John had barely made it up the stairs without toppling over.
Sherlock has always prided himself on his ability to stay detached, but seeing John in such a state had set off a full range of unpleasant emotions. Panic, fear, pity, confusion, affection. He'd quickly buried his face behind a book in order to avoid being discovered in such a fragile state.
After entering the flat, John had promptly swallowed three pills and an entire glass of water, thrown himself into his chair, and dozed off. Sherlock reasoned that it wouldn't do to let John sleep there, lest he begin to snore and disrupt his work. So it had simply made sense to gently nudge John's sleeping form into a upright position, grasp him firmly around the waist, and lead him slowly but surely to the closest bed. Which just happened to be his own. And if John's head somehow ended up tucked against Sherlock's neck, well, that was just how gravity worked, wasn't it?
And so, that was how Sherlock found himself perched on the edge of his bed, checking John's pulse ten times in a row (in order to get an accurate reading, of course) and watching his chest rise and fall. His book remains on his chair, abandoned, and the timer for his latest experiment rings incessantly in the kitchen, waiting for him to continue on to the next step.
One more minute, he thinks, reaching forward to tuck the blankets snugly around John's sleeping form. Just one more.
As a young child, John had often been ill. He'd told Sherlock all about his childhood during one of their stakeouts, as the sun set and a chill settled in their bones. They had huddled together for hours, expressing intimacy in the form of stories that had never before been spoken aloud, but saying nothing of their physical closeness. Sherlock can remember the hollow look in John's eyes as he spoke of isolation, resentment, and parents who rarely showed him affection. He can envision a small boy with sandy blonde hair, small and shivering, sent to his room with no more than an exasperated sigh and a feeble promise to check on him later. As a boy, Sherlock had been doted upon, and illnesses had been met with an unnecessary amount of overbearing love. What must it have been like for John, who shared his feelings almost as infrequently as Sherlock himself, to be left alone in a time of need? The thought fills Sherlock with an inexplicable amount of rage for the parents who neglected the man now sleeping restlessly in his bed. John is frowning slightly in his sleep, and heat radiates from him, even as he grips the blankets tightly around his trembling form.
Two hours have passed, and Sherlock has moved from his spot only once, dashing into the kitchen and tossing the timer out the window before the sound can disturb John. He has no idea what to do next, but leaving John's side is not a valid option.
"Hnf."
Sherlock snaps to attention, focusing on John's fluttering eyelids. They open slowly, and John begins to take in his surroundings.
"Ow."
"Oh, god. What hurts, John? Can you speak? Can you move? Tell me in exact terms what is ailing you."
"Sherlock? Hey, s'okay, just…feels like a fever, and my head…wait, are we in your room?"
"Yes, John, that's not important. Now tell me – what can I do for you? John?"
Sherlock's voice turns frantic as John's eyes become dazed and distant.
"Smells like you," whispers John, turning his face into Sherlock's pillow.
And then he loses consciousness.