It's not as though Sherlock doesn't feel. He does – anger, fear, delight, frustration, superiority, all are part of his day to day life. Particularly the last one, John would probably say. John feels all these things too, Sherlock knows. But the difference between the two of them – the difference between Sherlock and most other people – is that emotions for John are overwhelming. They affect his decision-making, they impact how he sees things. For Sherlock, they are detached. Useful for motivation, certainly in the case of anger or frustration, and useful for maintaining an accurate internal belief in his own abilities, in the case of superiority (usually in the face of insults), but not unavoidable. Not anything that can't be stamped down upon or removed if necessary.

But out there…

Withdrawal was one thing. That was frustration. It was hardly his fault that his mind needed to be constantly occupied, and even more so when he was attempting to distract it. And despite his behaviour, he knew the source was physical, quantifiable. Annoying, but necessary, and ultimately no cause for concern. He'd been through it all before and worse, on the occasions that Mycroft had seen fit to intervene and 'remove him from temptation' as he called it. He'd been a lot worse to Mycroft than he would ever be to John or Mrs Hudson, so it hardly mattered.

But out there…

The case had begun boringly enough. Sherlock had barely had his usual patience, which John would probably have called no patience at all. Superstition was the stuff of children and childish minds, as were conspiracy theories. But then, that odd choice of words… "gigantic hound"… it had piqued his interest. A puzzle was delight and amusement and something that would distract him from his cravings, at least for a time. He hadn't really thought that it would be a challenge, just something to shift him out of his London funk and pass the time with until the worst of the withdrawal symptoms were done – contrary to John's belief, Sherlock did know how to look after himself and occasionally actually did so.

But out there…

Darkness and fog; even Sherlock knew enough about popular culture to recognise the perfect setting for a horror film. He had been mildly concerned when John fell behind – uncharacteristically so, actually. A flicker of uncertainty. Most unlike him. But then John had caught up and Sherlock had quickly dismissed his previous feelings, putting them down to withdrawal causing a slight emotional instability or something like that. After all, he and John had not been on the best of terms for the last couple of days, probably something to do with breaking into Baskerville. Maybe John's military instincts were better ingrained than Sherlock had thought, making him unexpectedly uncomfortable with the idea. It wasn't an insurmountable problem.

But out there…

Everything had been confused, muddled – more so than Sherlock had felt for a very long time. He had been a child again, confronted with nightmares his mind told him did not exist. But knowing that a shadow is only a shadow doesn't stop it being a monster. He'd grown older, grown past that, and then… out there…

John was speaking. Sherlock tuned in, on the off chance that it was something important.

"…maybe we should just look for whoever's got a big dog."

"Henry's right," Sherlock heard himself say, almost unwillingly.

"What?"

"I saw it - too." He had to force the words out. Impossible, ridiculous, stupid.

"What?" The disbelief in John's voice was painful to hear, even as it mirrored Sherlock's own thoughts. His faithful… friend. Yes, that was right, even if he didn't admit it. His friend didn't believe him.

"I saw it too, John," he repeated, certain that John would understand. Despite their differences, John always did.

"Just - just a minute. You saw what?" John was confused. Understandable. Sherlock fought through rising nausea and uncharacteristic fear to clarify.

"A hound, out there in the hollow," he said, disliking the shape of the words in the air. "A gigantic hound."

He glanced at John, but the man was – was that a smile? That was not like John. John was a kind person, and even through Sherlock's skewed lens smiling at this point would be unfair. John was talking again, and Sherlock caught the tone and not the words. Not quite condescending, but something of that flavour.

"…we know, yes? Stick to the facts."

Despite his growing irritation, John being John calmed Sherlock slightly.

"Once you've ruled out the impossible, whatever remains, however improbable, must be true," he said carefully. Even in this state, he felt a hint of pride; that was well-articulated, even for him. Perhaps he'll write it down somewhere. John doesn't understand it, but maybe he'll put it in his blog anyway.

Sherlock picked up his glass, and what he saw there made him laugh.

"Look at me, I'm afraid, John. Afraid." Fingers shaking. Shaking? Sherlock Holmes does not shake. Sherlock Holmes is more in control than that.

"Sherlock."

John didn't understand – but he had been a military man, he knew the value of control over one's feelings, surely.

"I've always been able to keep myself distant." Sherlock took a sip of the drink. He had to make John understand, because once John understood then it'd be a simple human normal thing and therefore he'd be able to dismiss it. "Divorce myself from feelings. But look, you see?" He held the drink to show John his shaking hand. "Body's betraying me. Interesting, yes? Emotions. Grit on the lens, the fly in the ointment."

"Yeah, alright, Spock, just - take it easy," John said. Sherlock bit back a retort. "You've been pretty wired lately, you know you have. I think you've just gone out there and got yourself a bit worked up." John's Doctor voice now; he was concerned, but he didn't understand, Sherlock needed him to understand.

"Worked up?"

"It was dark and scary."

"Me? There's nothing wrong with me."

Why did he feel like this? Sherlock rubbed his temples with his fingers, made use of mental calming routines he was taught as a child, but nothing seemed to work. His breathing was unsettled, his mind with it. What he saw was real, at least to his eyes, but it can't have been, it can't have been –

"There is nothing wrong with me, do you understand?"

The restaurant fell silent, and from there the conversation only went downhill. Sherlock needed this proof, needed to sit there and take someone else's life apart, needed John to listen in amazement because this was normality, this was security, but he'd done it wrong and John was angry, properly angry and then he was left with a bitter feeling in the pit of his stomach and the sense that what he just did was completely pointless.

Sherlock stares into the fire and wonders if John has found the dogging group yet. With a small smile he breathes slowly, feeling calmer, and then turns to see one Louise Mortimer entering the pub. He flips out his phone and texts John.

Henry's therapist currently in Cross Keys pub S

John's reply is in all caps, as it usually is when he's feeling too cross to fiddle with the settings.

SO?

Sherlock replies, providing a photo when John clearly needs more motivation than just being asked. He then puts the phone away and returns to their rooms, knowing that John would rather not have his company during this… interview. The shared room is quiet. Sherlock gazes out of the window, alone with his fear.