Mycroft Holmes was sitting in his study at the Diogenes Club, reviewing his own hard copy of the documents he'd entrusted to John. It was an ordinary morning that became decidedly less so when he got the news that Sherlock had come to visit.

"Sorry," he said to the servant, "did you say Sherlock Holmes is here?"

"Yes, sir."

"Did he mention why?"

"He said—He said he wanted to thank his brother in person for his kind help yesterday."

Uh-oh. "Send him in."

Mycroft wasn't quite done mourning the loss of peace and quiet when Sherlock came bounding in. "Mycroft! Sorry for not calling ahead, but I knew you'd be here. Nothing like a familiar haunt when you're dealing with a national crisis."

"The door, Sherlock."

As Sherlock closed the door, Mycroft noticed that his brother's good spirits belied some obvious signs of stress and overwork. His eyes told Mycroft he wasn't getting much rest—probably not regular hours either, going by the state of his hair.

"Is the investigation going well?"

"Immensely," Sherlock said with a note of self-deprecation.

"I see you're making a real effort with this one."

"Am I?" Sherlock caught sight of his reflection in the window and ruffled his hair self-consciously. "I suppose so."

He seemed more distracted than usual. Mycroft was secretly glad that at least one of them was anxious to tackle this case, even if his little brother's gusto was currently keeping him from more important things. "Have you learned anything yet? It's been a week."

"I know it's been a week. Why does everyone keep reminding me?"

"Can I take that as a no, then?"

"You know everything I do, Mycroft." His frustration was palpable. "There's a lot of information to consider. It's too early to settle on any one theory."

"But you have theories, then?"

"Oh yes."

"I'm glad to hear it. For a moment there, I thought you were going to make me regret getting you that pardon."

"Regret? I don't think you'd dream of that." Sherlock helped himself to a handful of peanuts from the crystal bowl on Mycroft's desk. "I was expecting a thank you, at the very least."

"Thank you?"

"Yes, like that. I did only get rid of a man who had half your people under his thumb."

"Sherlock," Mycroft began, but he could feel his blood pressure rising, so he pinched the bridge of his nose and waited.

"Sherlock," he continued, "you blew a man's brains out after I specifically asked you to leave him alone. I think you can understand why I would be a little cross about that."

"But you are secretly pleased."

"Months of careful diplomacy going out in a blaze of gunfire—"

"I did you a favor, Mycroft; you know it and I know—"

"Oh, grow up." Mycroft knew Sherlock had a point, but he still could have strangled his brother for his rash interference. "You've no idea, Sherlock, all the trouble you caused by deciding to play the action hero, leaving me to clean up your…"

He lost his train of thought when he noticed the way Sherlock was looking at him. He knew that look—intense focus, to the point of overextertion, with the gleam of a child's curiosity that hadn't changed in all these years. You could always tell when Sherlock was trying to figure something out.

How much does he know? The great downside of being smarter than Sherlock was that Mycroft found it annoyingly difficult to predict what his little brother would and wouldn't notice. This meant that outsmarting him was tricky, but Mycroft usually found that it was possible. Usually.

Mycroft gave Sherlock his emptiest smile. "I sent Dr. Watson over with some of my files. I trust you've had a chance to look over them."

"Oh, yes, thank you; I'm sure that'll be useful. Of course," he added, "it's only useful insofar as the real mastermind actually knows about them."

"Sorry?"

"Oh, come on, Mycroft. You and I both know Moriarty isn't actually back. We saw his image, and that's all it is—an image, a smokescreen. Someone is going to great lengths to pretend to be Moriarty, which is why if they know about this—" he thumped the stack of papers on Mycroft's desk "—it's going to get a lot easier for me to predict their next move."

Mycroft pulled the documents away defensively. "Is that so?"

"Yes. They'll do whatever they expect Moriarty to do. The thing is—" Sherlock was pacing a bit, glancing around the study "—even if I don't know who's behind all this, I know a bit about them."

He must know it's not a coincidence, Mycroft thought suddenly. "Such as?"

"Our mastermind may have used Moriarty's image, but it still has a personal touch to it. A flair for the dramatic—I don't have to explain that to you…"

"Power and self-assurance. I don't have to explain that to you."

"Power—yes, of course, he'd have to be powerful to pull off something like that—"

"He, Sherlock?"

"But—yes, obviously—but he didn't do it alone, not by a long shot."

"Mm," Mycroft agreed as he busied himself with the documents.

"No?" he said as he suddenly realized he should be interested by that.

"Every screen in the country? Every television, every CCTV camera, every light-up billboard? That takes a lot of connections…extensive knowledge of criminal networks. No, I'm not dealing with only one person; that…that would be simple. No, you need to imagine an ant pile, a lot of ants in a lot of different tunnels all reporting back to the…No, not ants." Sherlock stopped his pacing and looked thoughtful. "Termites."

"Is this a very important insect metaphor, Sherlock?"

"I was going to say—" his tone was insistent "—termites reporting back to the queen."

Mycroft laughed to himself. So this was why Sherlock had interrupted his morning—to rattle off ideas and pretend like he had the first idea of what was going on. Then he imagined the termite network and the queen termite sitting on a termite throne and for some reason he had a thought about how his diet wasn't going all that well.

"Well—" he was starting to wonder what gave Sherlock the right, anyway, to come in here with his ramblings and his insect metaphors "—I'm sorry you're not getting any help from Dr. Watson."

"Did he tell you that?"

"You told me that. You wouldn't be here if you had anyone…more agreeable to discuss things with."

"So I couldn't just be here because I value your expertise?"

"No, Sherlock, because we both know you value your friends more than you value my…expertise."

Sherlock stopped pacing. "Is that what you think of me?"

Mycroft hummed noncommittally and went back to his documents. How foolish he'd been, he now realized, to worry that Sherlock had worked it out. It was a simple case of projecting: Mycroft tended to assume that Sherlock was still more like him than not, when in reality his little brother was probably more preoccupied with whatever had happened with Dr. Watson than he was with the case.

Mycroft looked up and saw that Sherlock was standing near his desk. Suddenly he found his brother's presence more than usually obnoxious. He sighed heavily. "Can I help you, Sherlock?"

"I'm not worried, you know. I'll work it out."

"Of course you will," Mycroft replied with every ounce of condescension he could muster.

"It's not me I'm worried about," Sherlock continued. "No, I'm worried about the queen."

"What, the mastermind?"

"The criminals need their Moriarty—he'll give them that presence they don't have on their own, that coordination…help them out with a little government vault, I shouldn't wonder…but they'll only leave the queen in power as long as he's acting in their best interests, as long as he's acting like Moriarty. So you see, he'll have to keep working with them. If he tries to abandon them, they'll turn on him. So, really, is the network working for the queen or is it the other way around?"

They were eye to eye now, Sherlock leaning on the desk, but Mycroft couldn't bring himself to be annoyed at this invasion of his personal space. He was thinking about the people he'd met with behind closed doors, bribing, bargaining, blackmailing—whatever it took for him to get the help he needed. The vault had been a necessary sacrifice, and it was just the beginning. He'd always known there would be trouble to follow, but what difference did that make? He intended to take care of it—in his own time and on his own terms.

But now Sherlock knew. Of course Mycroft had expected him to figure it out eventually, had planned for it, but frankly, he's expected to have more time. Time Sherlock would spend chasing after the usual suspects—masterminds and criminals. Surely his own brother would be at the bottom of that list.

All these thoughts passed through Mycroft's mind in the space of a few seconds, and then it occurred to him that Sherlock was waiting for a response. "Well," he said, "well, does it really matter at this point?"

Sherlock searched Mycroft's face. "You have connections. I know you keep tabs on people like Moriarty and Magnussen. You know people who are out there in the shadows, waiting for opportunity to strike…"

"Sherlock—"

"Will you help me?"

"Help you?" Mycroft was trying to remember the last time Sherlock had asked for his help.

"I need to find the network. Anything you know—will you help me? Anything at all."

There was that look again—that curiosity. What was Sherlock trying to work out now? Probably whether Mycroft knew the game was up. Mycroft almost wanted to tell him, but he couldn't, not yet, and he certainly couldn't do what Sherlock was asking. The detective had hit the nail on the head: Mycroft was working for the network, and right now that meant keeping his brother from finding out who had helped him. For now, they would have to be on opposite sides.

"I'm afraid," Mycroft said carefully, "that won't be possible."

Sherlock straightened up. "I see."

That was it. No pressure, no veiled threats—just disappointment. Sherlock turned to Mycroft's bookshelf, hiding his face.

"Sherlock," Mycroft said against his better judgment.

"Mm?"

"If anything changes, I'll let you know."

"Of course you will," Sherlock said absently as his fingers traced the spine on one of Mycroft's books. Mycroft couldn't read the title from where he was. It was an old hardback. He thought he might have gotten it from their parents' house.

"I know you'll help me," he continued. "I remember what you said to me, that you'd always be there…"

"I will."

"…that you'll always protect me, whatever it takes…"

Mycroft nodded slowly. "Did I say that?"

Sherlock turned to his brother with a half-smile. "I think so, yes."

Mycroft didn't know what had changed. Maybe nothing had, apart from his own perception. But as he looked at Sherlock's face, suddenly it was like he was looking into a mirror. Not just because he knew what Mycroft had done, but because he understood why. Mycroft knew his little brother would do his best to expose him, and he wouldn't expect anything less. But at that moment, he was sure that Sherlock understood what he had done, that he approved, that he would have done the same for him because maybe they weren't so different after all.

"Anyway," Sherlock said, "I should be going. I need to speak to John about something."

"Take care."

"Likewise."

As soon as the door closed behind Sherlock, Mycroft went back to reviewing his files. Plans would have to change now. He would have to try and stay a step ahead of his brother. And for the first time, Mycroft felt like he had a worthy adversary.