In a mad world, only the mad are sane. -Akira Kurosawa


"I'm not actually crazy, you know," Sherlock told him the next morning.

"Course not," John replied, taking a bite out of his toast.

Sherlock rolled his eyes. "Don't say that like you're just trying to placate me."

"I'm not."

Sherlock narrowed his eyes.

"Don't you eat?" John asked, changing the subject.

Sherlock waved a hand. "Not when I'm working. Slows me down."

"Add eating disorder to that list," John mumbled around crumbs. "And what could you possibly be working on? What do you even do?"

"I'm a consulting detective," he said impatiently. "The only one in the world, do try to keep up."

"Sort of like police?"

"Sort of. Not really. Better. Less rules, more results."

John snorted. "I'm sure you're a big hit."

Sherlock frowned, but nodded. "I used to work for Lestrade sometimes. Then my brother banned me from any sort of casework, private or consulting. I suspect it's part of what lead to Lestrade's breakdown, which only means my brother has more metaphorical blood on his hands." Sherlock looked gleeful at the prospect.

"And that... pleases you?"

"John, my brother is basically the entirety of the British government. Sometimes he needs to be taken down a peg."

"So what are you doing here then?"

Sherlock glanced around before leaning into John and whispering in his ear. "I'm undercover. Lestrade is too, more or less. I'm following the trail of a consulting criminal. He works here as an orderly. I'm pretending to be mad so I can infiltrate his web, and untangle it. No one ever suspects the crazy people."

He waggled his eyebrows at John, clearly waiting for a response.

John nodded slowly, wondering how much of what Sherlock was telling him was true. If his diagnosis was any of the number of things he'd mentioned, then he could be a pathological liar, or at least have no qualms about throwing out lies at every turn.

But Sherlock was a genius; that much was certain.

Of course, even geniuses weren't immune to delusions. John supposed that could be what this was. Sherlock could believe he was a detective, undercover in a psych hospital, because it was easier to deal with than the truth. He adapted some of the residents into his delusion. Of course, that begged the question why he'd only chosen Greg. And why he'd chosen to befriend John.

Sherlock seemed to be made of questions, and no answers.

Still, there couldn't be much harm in going along with his delusion, if that's what it was. There was still the slightest chance that Sherlock was telling the truth, and John wasn't going to bet against it, even if it did sound impossible. And mad.

He was in a mental hospital, he couldn't get more mad than this.

So he bit.

"A consulting criminal? What's that?"

Sherlock's face darkened. "This man sets up crimes for people. He's the mastermind of a million different tiny schemes, none of which seem related, or perhaps even important. A death that's only slightly suspicious here, a disappearance there, occasionally something bigger, like a robbery."

John frowned. "What, he's for hire?"

Sherlock nodded. "Exactly."

"So, criminals go to him wanting their crimes booked up, like a holiday?"

Sherlock nodded again. "Novel, isn't it."

John frowned. It certainly sounded ridiculous, although that meant nothing about reality, since many real things also sounded ridiculous. (Honestly, deep fried butter? Animals with florescent genes? Who was he to judge what was real or not anymore.) "Who is it?"

Sherlock averted his eyes. "I can't tell you that yet. It would compromise the investigation as well as your safety."

"Oh, well, as long as I'm safe," John sneered. "Since I'm sure that's what this is about."

"You don't have to believe me," Sherlock snapped, picking at an invisible thread on his dressing gown. "No one does. I don't need people to believe me to make it real."

John blinked. "Did you ever think that was maybe the problem in the first place?"

Sherlock looked up from his dressing gown at him. "What's that supposed to mean."

"Look where you are Sherlock," John said gently. "Perhaps some beliefs are best left behind."

Sherlock blinked. "That's just what he wants," he whispered, looking away, almost like he was unsure.

"Of course," John confirmed, nodding. He could tell he wasn't going to get anywhere else with Sherlock.

He heaved himself to his feet. "Shall we go see what the activity is for today?"

"Music therapy," Sherlock said distractedly. "It's a cycle of twelve days-"

"Get up," John ordered. Sherlock looked surprised, but obeyed. John smiled inwardly. Some of his captain side coming across perhaps. "We're going."

Sherlock rolled his eyes, but followed John.

It turned out, he was quite good at singing. And playing the piano. And he mentioned that he trained on the violin.

The music therapist seemed delighted, and promised to bring a violin the next time.

(Which, Sherlock reminded John, was in twelve days.)