The room was still and dark, with only the table lamp and the lights outside lifting the darkness and only the flash drive to show that John had been there.

Sherlock was dozing off at the computer, tired in his mind and in his body, but he wouldn't even think of going to bed. His thoughts were still humming away—not in sequence, not running through information systematically as they should, but repeating the same handful of points over and over and not getting him anywhere.

And even when his own thoughts went quiet, there was always the voice in the back of his head—a familiar voice droning on with words that he couldn't make out except for a phrase here and there: "balance of probability," and "brother mine."

"Why can't you just leave me alone?" he asked the walls.

As if he needed Mycroft to drive home how spectacularly badly he was handling this case. That was the gist of it, anyway—his older brother telling him how stupid he was because wasn't it obvious…

No, it wasn't obvious, because the rules of the game had changed. They'd changed when Sherlock Holmes shot an unarmed man in the head at point-blank range. And he'd realized, with some surprise, that murderer was just a word and that sometimes it was a word to describe someone making good on a vow to protect his friends no matter what. He didn't need anyone to justify his actions to him. Least of all John.

Sherlock had asked his questions for a reason. At some point, if things got much worse, Sherlock's life wasn't going to be worth Moriarty's return. Sherlock didn't know when that would be, but he'd liked to think John would know. Sherlock was sorry he'd been rude earlier. It had seemed like the only way to get John to leave, the only way to get him to stop answering questions Sherlock had suddenly realized he didn't want answered.

"You're not actually distracted by all this, are you?"

The voice rang out clearer than before, as if someone had actually spoken. Sherlock looked toward the sound of the voice, and there was Mycroft, appearing as Sherlock's mind expected to see him—sitting in Sherlock's chair, hand on his umbrella, looking substantial about the waist and more than a little contemptuous.

"Why are you here?"

Mycroft tilted his head back. "You know why I'm here."

"What does that mean?"

"The rules of the game have changed, little brother, and your heart is rejecting what your brain already knows. Or haven't you been paying attention? Falling asleep like that, your increasing lack of focus—Your system is turning against itself. I told you once that caring wasn't an advantage. Thank you very much for proving me right."

"Well, if we're talking about caring," Sherlock began, but he knew Mycroft had a point. All in all, he was functioning at about the level he'd expect to if he were being inhibited by something in his subconscious.

Sherlock took a seat in John's chair. "All right. Let's say you're right. Why would you care about that? And why are you here? You didn't just come here to gloat."

"No, I came here to help. You know you need me. The fact that I'm here at all proves that. Do you know why it's me, Sherlock, why it's always me?"

"Of course I do," he mumbled. He was thinking about John and how he'd told him he wanted to be alone, and yet here he was talking to a mental version of his brother.

"John can't help you—and he won't now, not after you pushed him away like that. If you want him on your side, you're going to have to be nice." Mycroft twirled his umbrella contemplatively. "They're always a bit high-maintenance, aren't they? The ordinary people."

"Well, so are we."

"No, Sherlock; so are you." His tone was hard and his face had that look Sherlock hated—the look that said you know I'm right; you're just to stubborn to admit it, which was usually an annoyingly correct assessment. "You act like one of them, but we're still more alike than you care to admit."

"Well, maybe I don't want to be," Sherlock spat, and then he realized the absurdity of his situation. He wasn't the high-functioning sociopath he'd been six years ago—that was obvious—but he'd thought he could change just enough without losing who he was. Instead he was caught in the middle—too human for his brother and still too machine for John.

Mycroft dropped his gaze. "Sherlock, has it occurred to you that maybe you're having trouble catching your criminal because you've forgotten how to think like he does? This whole business of turning criminal to protect you—Well, it's not exactly something out of Dr. Watson's book, is it?"

"Dr. Watson doesn't have an opinion on the matter."

"Really?" Mycroft smiled. "Well, thank goodness for that."

Mycroft stood and advanced toward Sherlock. He reached into his coat, and Sherlock saw that he had something in his pocket.

Sherlock flexed his hands nervously. "You're wrong about me, just so you know. I understand all that. I know sometimes you have to do something…something you didn't think you could do. Or don't you remember what I did to Magnussen?"

"Yes. That was a knee-jerk decision that revealed who you really are. If you're going to find an explanation for Moriarty's return, you're going to have to find that man again. The man who'll do whatever it takes to protect the people he cares about. Even if it isn't particularly nice."

He pulled a book out of his coat pocket and held it out to Sherlock. Sherlock didn't have to look at the title to know what it was. The cover was green and hardback and worn, the cover of a book that was older than either of them and had been read many, many times.

It had been years at least since Sherlock had thought about this. His heart was beating faster as he took the book from Mycroft and looked at the title. It was a short story compilation: The Adventures of Detective Dupin, by Edgar Allan Poe. The book had been a fixture in their childhood home for as long as Sherlock could remember, but it wasn't until he was about seven years old that it found its way into his bedroom, his schoolbag and his heart.

He was a bright child—not yet the deductive savant he would become but studious for that age and endlessly curious. Reading was his latest pastime—during his free time, in class; anytime he was feeling bored—and one day, when he was looking for something new, his mother had handed him this well-worn book of detective stories.

By his second time reading it, people were noticing and were starting to talk—the younger Holmes boy who always had his face buried in The Adventures of Detective Dupin. The older boy must have noticed (Sherlock had forgotten his name a long time ago) before he'd snatched it away in the courtyard, and Sherlock had screamed and slapped and reached as high as his arms could go, but the boy laughed, held the book just out of reach and then ran away, and Sherlock didn't know what to do.

He didn't mean to tell anyone. He hoped he would find some way to get the book back before his mother found out. At dinner, something must have shown on his face because she asked him if he was all right. He said he was, and she hadn't pursued the matter. He was good at hiding his feelings, even then. But the one person he couldn't lie to was Mycroft.

That was how he ended up after dinner in Mycroft's room, teary-eyed, explaining how their mother's book was gone and there was nothing he could do and how powerless he'd felt against the older boy. The brothers didn't get on well as a rule, and Sherlock was worried Mycroft would tease him too. Instead, he'd listened quietly until the story was finished and then told Sherlock to go to his own room and to stop worrying about the book.

The next afternoon, Sherlock was in his room when he heard a commotion down the hall. He put his ear to the door and listened. He heard his father's voice and Mycroft's, and there was trouble—Mycroft had been suspended; something about fighting with a younger boy. His father didn't sound angry so much as confused, and rightfully so because Mycroft rarely got in trouble at school and he never fought anybody. For his part, Mycroft didn't elaborate on the incident except to say that he was sorry for the trouble and he'd try not to make a habit of it.

Moments later, there was a knock at Sherlock's door. It was Mycroft. Sherlock didn't mention what he'd heard, and Mycroft didn't bring it up. Instead, he handed Sherlock the worn old book and told him to keep a better grip on it next time. And after Mycroft closed the door behind him, Sherlock stood there a minute, staring at the door, his heart swelling at this unexpected act of love.

"That is who we are, Sherlock. No matter what, for the right person—whatever it takes…"

Sherlock awoke with a start in the empty flat. As he sat up, his gaze fell on the chair across from him. Mycroft was gone. Apparently he'd said all he needed to say.

Sherlock stared for a moment, then broke into quiet laughter. "Oh," he said, "you—you…"

Now more than ever, he was sorry he'd been rude to John, because only now were the pieces falling into place. If John hadn't given his approval to their Moriarty, probably Sherlock wouldn't have entertained the possibility that Moriarty's supposed return had been orchestrated by someone so close to him, someone with the best of intentions, the only person with the means and the motive to save Sherlock's life.

But Mycroft?

He'd hidden it well if it was him, and Sherlock wasn't saying it was. He tried to think back to that phone call when Mycroft had told him the exile was off, how he'd acted when they'd talked on the plane. He hadn't seemed particularly surprised by any of it—but then, that was Mycroft. He wasn't one to show his hand.

And if he'd cared much that his little brother wasn't going off to certain death after all, he certainly hadn't let on. Just a smart Well, I certainly hope you've learned your lesson and a quick explanation. That was all right. That was how they communicated. And naturally, Sherlock hadn't replied with anything warmer than Who needs me this time?

England.

Sherlock stumbled on the word. It stood out to him like a signpost. It reminded him of something that he almost remembered. Something that had happened recently but also so long ago…

He crossed to his own chair, sat down, closed his eyes and imagined himself sitting there in 1895. He remembered, as clearly as if it had really happened, being there with the other John and the other Mary and the other Mycroft…

The goal had been to find possible explanations for how a person who had shot himself in the head could apparently still be alive, and most of the details had been oriented to that. But then there had been that business of Mary working secretly with Mycroft. What was that about? Sherlock hadn't been there when it happened, not the other version of himself, but he remembered Mary getting the card with the mysterious mark of the letter M—she didn't even tell Mrs. Hudson where she was going; when the landlady had asked who it was who needed her, she'd just said…

England.

The connection rang out in Sherlock's mind: Mycroft is the British government. Mycroft—England. Mycroft had told him his heart was rejecting what his brain already knew, and apparently his brain had figured it out a long time ago. In his drug-induced state, he'd interpreted Mycroft's response—whether he'd intended it that way or not—as a royal synechdoche.

England needs you, Sherlock. I need you.

And suddenly Sherlock realized that he really was very tired and that he should probably get some sleep. There was much more work to be done—certainly he'd have to investigate some more to determine whether it really was Mycroft—but now he could rest because he understood, and it was all right. And even if it wasn't Mycroft, it would have to be someone like him, like Sherlock—someone like…

Sherlock paused halfway down the hallway. He was getting that feeling again, that feeling of almost remembering. He thought about the mark of the letter M on the calling card for Mary, and there was something else, too, something he'd seen in the other place…

"Miss me?"

Then he remembered completely. It flashed before his eyes, the note that had been tied to the sword in the victim's chest—Miss me? The original phrase was Did you miss me?—he'd known it at the time; Mycroft had explained—but in the dream it was shortened: two words, two letter M's harmonizing with the mark on the calling card, spelling out a truth he couldn't let himself know because it was too terrible unless you looked at it from the right perspective.

MISS ME

M.M.

M for Moriarty…or M for Mycroft?