Mycroft Holmes frowned at the building before him. More a fairytale castle than a defensive structure, it wouldn't look out of place at Disneyland Paris.

Not that Mycroft had ever been to Disneyland Paris, but the Barnabys had sent photos when they'd taken Harry there for his tenth birthday, so Mycroft knew his comparison was apt.

He gave quiet thanks to whomever had created the rings he, his Sentinel, and Wendell Granger wore. Otherwise, they wouldn't have been able to see the castle at all.

"Bloody hell." The soft exclamation came from Granger. Mycroft echoed the sentiment but would never say so aloud.

Mycroft turned to the six members of the Magic and Military Service - colloquially, the M&Ms - he'd chosen for this mission.

"You are aware that this is a protective detail," he told the M&Ms. "Lethal force is within your remit only if it is first used against us, or there is a threat that cannot be handled in any other fashion."

"Understood, sir." Lieutenant James Benedict offered him a salute and with a word, his troops fell into protective formation.

"You know where to go?" Mycroft asked Barnaby.

"It's dinnertime, sir," Barnaby said. "Nearly everyone will be in the Great Hall."

"Who won't be?" Gareth asked.

"Anyone in the infirmary," Barnaby replied. "Necessary infirmary staff. Possibly one or two others."

"Trelawney," Ben Jones - the distinction was necessary, as Rhiannon Jones had accompanied them. "Divination professor. She rarely leaves her quarters."

Rhiannon Jones snorted indelicately. "Potted all the time, that one. Then again, if I had visions of the future - or even blackouts, if it's true that seers don't remember the prophecies they make - I'd drink like a fish, too."

"And the headmaster is the big deal in the room?" Gareth asked.

"For political power, absolutely," Lieutenant Benedict said. "For magical power? McGonagall, Snape, and Flitwick are all well above average. Flitwick was a champion dueler in his youth."

"Right, then - you'll keep your eyes on them, and I'll handle the headmaster." Mycroft actually felt almost as confident as he sounded, thanks to a parchment in the breast pocket of his suit coat. "Let's go, then - no sense hanging around out here."

Any other time, Mycroft would've enjoyed examining the building Barnaby and Jones - both Joneses, actually - were guiding him through. Tonight, however, he was a man on a mission for Her Majesty, and he focused on calming and centering himself for the coming confrontation.

Finally, Barnaby opened a pair of doors that stretched at least again as tall as the tallest member of their group. Beyond them, Mycroft saw a dining hall that could have been at any boarding school in England, except this one had only four long tables for students and one table for the staff.

Barnaby strode up the gap between the center two student tables and then stepped a little to Mycroft's left, allowing him and Gareth to approach the … throne? Surely not, but the ornate chair at the center of the staff table resembled one. The man who sat in it, however, resembled Gandalf the Grey - except Gandalf never wore parti-colored robes with animated butterflies all over them.

The Gandalf lookalike rose from his chair. "Welcome, visitors. Some of you I recognize."

"Allow me, Headmaster Dumbledore," Ben Jones said. He'd taken up position to Gareth's right, and the M&Ms were arrayed in a protective formation. "Behind me is Guide Wendell Granger, father of Alpha Guide Hermione Granger, a first-year here at Hogwarts. To my immediate left is Gareth Mallory, Alpha Sentinel of the United Kingdom. To his left is Mycroft Holmes, Alpha Guide of the United Kingdom. I believe you or your staff will recognize the rest of us."

"And to what does Hogwarts owe this visit?" Dumbledore asked with a kindly smile and a twinkling look over his half-moon glasses.

"Sentinel Potter wrote to us of a threat to his tribe," Mycroft said. "We're here to help him deal with it."

"A threat?" Dumbledore repeated, either truly astonished or an astonishingly good actor. "At Hogwarts? Surely not!"

"Hogwarts is one of the safest places in Britain," the woman to Dumbledore's left, in emerald green robes and a matching witches' hat, declared.

"Perhaps, perhaps not," Mycroft said. "But as Alphas of the United Kingdom, we have received a complaint from one of our tribe, and we must investigate. I'm sure you understand."

"There's really no need," Dumbledore began, but Mycroft wasn't in the mood for social niceties.

"My apologies, Headmaster, but it wasn't a request." Mycroft reached into the breast pocket of his suit coat and withdrew a document. He opened it and turned it to face the headmaster. "Her Majesty has been informed of the threat to her underage subjects at Hogwarts. To misquote her great-great-grandmother, she is not amused."

Dumbledore waved his hand, and the document - actual parchment, unless Mycroft was much mistaken - glowed an angry red. Dumbledore looked shocked, and Mycroft smiled thinly.

"One does not command the slightest portion of Her Majesty's magic, Headmaster," he said. "You may, of course, examine the commission."

He handed it over and watched Dumbledore's expression grow more sober as he read.

"I don't understand why Her Majesty is concerning herself with a school matter," Dumbledore said finally. "But the commission is quite clear. Professor McGonagall will give you a tour of the castle-"

"I'm sure Harry can take us." Barnaby turned to scan the assembled students, and Mycroft felt a surge of concern when the man whirled back to face Dumbledore. "Where's Harry?"

Dumbledore smiled with an affected congeniality that made Mycroft want to hit him. Surely Gareth was plotting to do much worse.

"It is a large school," Dumbledore said. "And, while students are expected to be at meals-"

Barnaby growled with such ferocity that all three Guides in the party reached out to steady him. Only his own Guide touched him, but Barnaby visibly calmed as three layers of empathic buffering settled around him.

"I'm not saying the headmaster doesn't deserve your wrath, Barnaby," Mycroft said. "But your priorities at this moment are clear. Find your son, Sentinel."

It was a low blow, using a Guide's skills to prod Barnaby into doing what he was going to do anyway. Mycroft had long owned the darker part of his nature - the part that made him so effective in his career - even if he disliked using it on general principle.

But with the young Alpha not where he was supposed to be, and a documented threat in the school, time was of the essence. Thus, he used his gift and hoped he was using it justly.

Barnaby nodded, once, and crossed the room, passing by each table in turn.

"Of course we'll help you search," Dumbledore began.

"Of course you will not," Gareth snapped back, saving Mycroft the trouble. "Our men have trained together and know how to work as a team. The rest of us are Sentinels and Guides and know how to work with each other."

"Leaving me out on purpose, Alpha?" Rhiannon Jones asked with a fair amount of humor.

"Never," Gareth replied, quite seriously. "But Guide Jones assures me you know your way around working teams like this."

The woman nodded, and it was then that Barnaby called to them. "This way."

Unsurprisingly, Ben Jones was the first to follow his Sentinel. Somewhat surprisingly, Rhiannon Jones - who appeared to be eighty if she was a day - was the second, only a few paces behind. Wendell Granger followed next.

Mycroft lingered while Gareth gave quiet orders to the M&Ms. Then the two of them were hot on the trail of the ones who'd left first, two of the M&Ms keeping pace with them.

Any other time, Mycroft would've been fascinated by the castle, especially the portraits that appeared to be moving. Now, though, he concentrated on keeping up with the Sentinels in the group, oddly reassured that the M&Ms also lagged a little behind.

"Bugger!"

The exclamation came from Barnaby as he stopped in front of an open door, through which Mycroft could see a…three-headed dog? Facing down some kind of overgrown cat?

The M&Ms readied their weapons - wands, not the handguns they carried - but Wendell Granger's sharp exclamation stopped them from firing.

"Hold! That's Hermione's spirit animal!"

And now, yes, Mycroft could feel the cat's psionic presence, and he cursed himself for paying more attention to the castle than their mission.

"Bloody large cat," Gareth muttered.

"Not a cat, really," Ben Jones said. "A chimera, right?"

"Yes," Granger said simply. "Do you need help, Chess?"

The cat - no, the chimera, and what did that say about the "lizard" Mycroft had seen with Harry Potter all those years ago? - gave a negative-sounding rumble.

"Right, then," Granger said. "Let's go."

"Does your daughter play?" Barnaby asked.

"Play?" Granger repeated with a frown.

"Chess."

Granger chuckled, though it had a grim undertone. "No. She'd just watched a cartoon of Alice in Wonderland when she first met Chess - which is short for Cheshire."

Barnaby just nodded before leading the way to a trap door open in the floor.

"I think my men should go first from here," Gareth said, and Mycroft couldn't agree more.

They'd known there was a threat, but after facing a Cerberus straight out of mythology, for the first time in his life, Mycroft Holmes felt useless and unnecessary.

He resolved never to feel that way again.