A/N: A little Mycroft, as a treat. And the start of an even more promising friendship.

Mycroft's dormitory was housed in a large, rather blocky brick building named Angelo's. He didn't have a room to himself, not that he had expected to; he was here on scholarship, and the Dursleys, while financially well-off, were not among the old nobility who traditionally sent their sons to the school. The roommate thing would have been more an annoyance than an actual problem, were it not for Sherlock's bequest.

Mycroft waited until the weekend and made certain his roommate was out for the day before removing Fluffy from his trunk. He handled it with a ginger distaste.

"How to dispose of you?" he said aloud into the empty room. Fluffy mewed indignantly in response.

"Don't be like that," said Mycroft irritably, setting the semianimate cushion on the bed with his other pillows. "If you'd only keep quiet we wouldn't have a problem, now would we? It's a miracle Atkin sleeps like a log. I've been kept awake all night by your incessant meowing. Cut it out and I could keep you on cream and tuna, wouldn't have to stuff you down in the bottom of my trunk—"

He was joking, of course, but Fluffy spat at him, a surprisingly lifelike sound. Mycroft frowned down at it.

"Do you actually understand what I'm saying?"

The cushion was silent. Mycroft turned away, feeling rather stupid. He dug into his trunk again and unearthed a sophisticated mobile from a pair of wool socks. Laptops, smartphones, and the like were forbidden at Eton based on their usual vapid uses, which were hypothesized to keep students from sleep. Mycroft, however, had no interest in games, pornography, or social media. Aside from news, email, and an e-book reader, the only applications he had downloaded onto his phone were of his own design. Mycroft pressed on one of these icons and waited patiently. Wherever Sherlock's school might be, it most certainly would not have Wifi for his device to hijack.

Still, he wasn't prepared for the message that flashed up at him from the tiny screen.

LOCATION NOT FOUND.

Mycroft frowned, and tried again. The tiny piece of electronics he'd implanted in the lining of Sherlock's trunk—nothing sophisticated, merely a GPS and listening device—had its own network signal, and a strong one. He'd designed it himself. Even in the mountains or ocean it ought to reach him from here; it had been obvious from Hagrid's accent and demeanor that Hogwarts wasn't outside the UK. Scotland, most likely. And Berkshire was no more than 500 miles from there. Something wasn't adding up.

LOCATION NOT FOUND.

Had Sherlock already found and disabled the device? It wasn't unlikely. Although not Mycroft's equal, Sherlock was by far the brightest person he knew. Ever-suspicious of his privacy, Sherlock could even have foreseen Mycroft's play. Although electronics were not among Mycroft's usual preoccupations.

The justification for Mycroft's hope was the thrall his cousin's mind fell under when exposed to novel stimuli. Sherlock had plenty to think about, embarking on his new life. If Mycroft's bug was discovered, he expected it to take a week or more. It was galling to admit that he might have been found out so soon. Mycroft took refuge in the thought of an electrical storm or some similar disturbance wreaking havoc with the signal; he would try again at the earliest opportunity. Concealing the phone in his luggage again, Mycroft returned his attention to Fluffy.

What he really ought to do was bury the thing somewhere a drunken student mightn't find it, but Mycroft disliked getting his hands dirty. There was only so much he was willing to do for the Statute of Secrecy so early in their relationship. Let wizards clean up their own messes...

But don't, for the love of all that is holy, let the thing be linked to him.

"Dumpster, I suppose," he said to himself, casting about the room for a bin liner or three. No sooner had he said this than Fluffy hissed. Again, it sounded just like an actual cat.

"Quiet," Mycroft said sharply. "Can you really not see the imposition this is?"

Fluffy squinted up at him with its unsettling black button eyes.

"Stop that too," snapped Mycroft, pulling on his trousers. "You're not making much of a case for yourself. We're going on a fieldtrip, you and I."

Fluffy gave him a look that was absolutely heartbreaking.

"How do you do that with plastic eyes?" Mycroft demanded. "And more to the point, why? Do you really think I'd take pity on a thing Sherlock sicced on me?"

Muted purring.

"Don't do that. Don't like him. It's his fault you're here."

The purring ceased.

"That's right," said Mycroft, glancing out the window to see who was around. Most of the students, fortunately, were attending a beginning-of-the-year cricket match; he could easily make a foray to the dumpster unnoticed. "You're unwanted. Abandoned. Rest in peace, Fluffy, because you do not, unfortunately, fit into my educational ambitions. Or, you know, the 'Muggle' world in general."

A plaintive, squeaking sound.

"Shut up," said Mycroft viciously, giving up on the bin liner and wrapping Fluffy in a towel. "You and I are not the same."

Mrow.

"I'm not a bright-pink cushion with half a synthetic brain cell, for a start."

Fluffy mewed again, more insistently, and Mycroft grimaced. "That's beneath you. You've been hanging around Sherlock far too long."

The towel vibrated. It was purring again. Mycroft rolled his eyes. "No, I'm sorry. Any amount of time spent with Sherlock is too much. He wasn't giving you attention, he was experimenting. Stop being flattered."

They went back and forth while Mycroft dressed, almost beginning to enjoy himself. Was this why Sherlock always kept that plastic skull in his room, the one he expected Mycroft not to know he had stolen from the school science lab? Mycroft could swear he'd heard him talking to it sometimes. And Fluffy, to be fair, made better conversation than most of Mycroft's classmates so far.

He was really, truly losing it.

"Look," Mycroft finally said, gathering Fluffy under one arm. "It's not fair, okay? Wizards walking into my life and out again, and I'm supposed to go on like nothing has happened? Like this never happened?"

He plucked an age-yellowed letter from his trunk and perused it for the hundredth time, frowning. It wasn't one of Sherlock's, though it was written on the same heavy parchment. Mycroft had taken it from his mother's dresser before leaving for school. No matter how many times he deciphered the extravagant handwriting, the words never carried an air of finality. Merely one of intermission. What was real, what was safe, what did the future hold for his family, or his cousin? Not even the wizards seemed to know.

Again the thought came to him: Sherlock isn't playing by their rules. Why should I?

Sherlock had resources he didn't, that was why. A situation both novel and unwelcome.

But he, Mycroft, had Sherlock. If he could buy his trust. And he could not kid himself that their shared childhood had made a spectacular start. He stood for a long moment in indecision.

"Fine," said Mycroft at last, stuffing Fluffy back into the trunk. "I'll slip you some salmon after dinner. But one more sound, and you're over."