The Doctor turned on his heel to head back to his desk. "Just let me put this away and –"
"Doctor," Lindsay interrupted.
He paused, and Lindsay pointed her wand at the parchment. It struggled free of his hand and zoomed to his desk.
"Ah," the Doctor said with a short nod. "Right. Gotta get the hang of that. Blimey, that'd be handy."
"And we're off," Sherlock said, striding to the door before the Doctor had finished speaking. "I think we should start on the south side –"
He was interrupted in his turn by Professor Flitwick, who barely jumped to the side in time to avoid the collision in the doorway. He cast a disgruntled look up at Sherlock, but focused on the Doctor at once.
"Smith, the headmistress said to come fetch you. There's been another incident in the kitchens."
The Doctor blinked. "Right. I'll be right there." He looked at the trio of students before him, and back at Flitwick's impatient face before continuing, "You three go along now. It's too nice a day to waste inside."
He gave a slow wink as he passed them and mouthed courtyard, though his movements were so exaggerated that it took John a few seconds to be certain that was what he had actually said. They let the professors precede them into the hallway and Sherlock took the lead, keeping them just far enough back that they seemed to be out of earshot, but could still catch snatches.
" – can't have happened more than a few moments before I came to fetch you," Flitwick said, his voice rising in agitation. "Another one taken, just like that."
"Taken?" The Doctor repeated. "Not eaten there?"
"Precisely," Flitwick said. He cast a glance over his shoulder and lowered his voice so they couldn't hear his next words.
"Up the flue again?" The Doctor asked, not modulating his pitch in the slightest.
Flitwick shrugged and spoke again, though the only words John could make out were "assume," "vanished" and "elves didn't see."
Flitwick sped up his pace so even the Doctor had to lengthen his stride to keep up. Sherlock didn't do the same, allowing the adults to reach the stairs well ahead of them.
"Didn't take the flue," he muttered. "Why?"
"We just lost our chance to find out," John said, hurrying the last few paces to the top of the stairs and seeing the professors at the foot of the flight. "And do we know for sure it didn't?"
"Only logical reason for that combination of words, John. And Flitwick would have been suspicious if we'd kept pace. He knows I eavesdrop better than most."
"If it didn't take the flue, do you think it's still in the kitchen?" Lindsay asked.
Sherlock made a noncommittal noise. "A deviation from its pattern, another one. It's getting rather alarmingly erratic." He smiled suddenly. "Good news for us."
He'd turned and bounded down the steps before John could formulate the words, "How is it good for us?"
Lindsay clapped him on the shoulder. "C'mon. I'm sure he'll explain." She hopped onto the banister. "Whether he needs to or not."
She let go of the gargoyle at the landing and sped off down the slope. John chuckled, but took the stairs the old-fashioned way. The last time he'd taken the banister was one of the first DA excursions the year before, when the novelty of being out after curfew had yet to wear off. Perhaps it would have been advisable in this case, but he didn't like to associate that relatively carefree moment with this one.
The others were waiting for him when he hopped the last few steps, disagreeing already.
"I still say we could sneak in without them noticing," Lindsay said.
"It won't have stayed in the kitchen," Sherlock retorted. "And if it did, I rather think the dozens of house elves or perhaps the two professors going in search of it might catch a glimpse."
He was scanning the walls with his eyes already. "If we assume it didn't go out the flue and it's not still in the kitchens, what are our other options?"
"It could have come this way, like it did that first night you found the scratch marks," Lindsay suggested. "When the door opened to let them in, it could have sneaked past them. You said it has the ability to blend in with its surroundings."
"Or the Great Hall," John said, the words coming out almost before they'd registered as thought.
"What?" Sherlock asked, his voice sharp with interest.
"The Great Hall," John repeated. "How do you think they send all the food up? Remember, Lindsay? They've got the doors by each table so they can take care of messes and magic the food on and off the plates without people noticing." Sherlock was staring, so he pressed on. "We went through the kitchens several times last year for the DA. I know where the openings are. We can at least check."
Sherlock nodded and turned toward the double doors without further comment. The sight of the Slytherin boy leaning against the wall beside them pulled all three up short.
"Moriarty," Sherlock said, his voice somehow deeper. John thought he'd done something to his collar, too, making himself look a bit taller and more impressive than usual.
"Holmes." Moriarty's gaze slid over Lindsay and John. "Odd company you keep these days, even for you. I suppose when you get truly desperate –"
"Would you mind shutting up now?" John broke in. He could feel Lindsay and Sherlock both staring at him, but he found the boy as unnerving as he had two days previous and was in no mood to waste time on him. "We've got business to take care of, and you're keeping us from it."
Moriarty pushed off from the wall and walked up to John, smiling in that reptilian way that made John's skin crawl. He stopped mere inches from John's face and turned to grin at Sherlock. "I think I can see why you keep this one around. Good little watchdog, isn't he?"
John had just clenched his fist and was in the process of convincing himself not to drive it into Moriarty's jaw when Lindsay's wand came between their faces and settled with the end firmly against Moriarty's cheek.
"I think he said to shut up, and I quite agree with the sentiment," she said.
Jim chuckled. "A pair of them, then? Well, isn't that adorable?" Lindsay's wand pressed harder into his cheek, but he merely stepped back a half step and focused on Sherlock again, who was watching the proceedings with a bemused expression. "If you're up to what I think you are, you should just run along to your next class and forget about it."
"Really? Well, if the great Jim Moriarty has spoken –" Sherlock said sardonically. "What's the matter? Haven't covered your tracks as well as you ought this time?"
John furrowed his brow, trying to follow Sherlock's reasoning to how the Slytherin could possibly be involved with the alien, but Jim was laughing, and the sound made his skin crawl.
"I'm not the one who put those kids in the hospital wing," Jim said, his voice dripping creepy innocence. "I just think you ought to stay out of it. Consider it a friendly warning."
"Yes, well, thank you for your concern. Now leave," Sherlock said, opening the doors to the Great Hall and motioning to the Gryffindors to follow.
John unclenched his fist with physical effort and turned away from the smirking Slytherin. It took only another breath for Lindsay to lower her wand and follow suit. Whatever Moriarty's involvement or lack thereof, they had a creature on the loose and a trail growing colder by the moment.
The Great Hall was empty. John expected it to be so, but it still felt odd to be there alone in broad daylight. Sherlock's gaze went straight to the floor, keenly checking each flagstone for markings. John and Lindsay guided him along the tables, pointing out the moveable stones the house elves used.
"Aha!" Sherlock cried as they turned down the length of the Ravenclaw table.
A stone was slightly out of position halfway down the aisle. Sherlock dashed up to it, sliding into place beside it almost flat on the ground. He had his wand out, and was already following the miniscule markings he found as Lindsay and John caught up to him.
"Up, over the table," he muttered, moving from the horizontal position to standing, then onto the bench. "Over to the Slytherin table." He followed suit, hopping to the ground between the two tables and then onto the Slytherin bench. "And from here – up the wall, perhaps?"
John and Lindsay clambered over the Ravenclaw table and dashed around the end of Slytherin to catch up.
"Sherlock," Lindsay called, pointing to a spot several feet over on the floor. "Blood."
Sherlock vaulted forward to examine it. "Still fresh. Not left more than two minutes ago. So if it didn't come out the doors, and the windows are still intact, what does that tell us?"
A drop of blood fell from somewhere above and splashed on the stone beside the first. The trio looked up into the bright, near-cloudless enchanted ceiling. It was impossible to see if anything lurked beyond the blue barrier.
"It's still here."
John stowed his wand in his robe and turned to the wall. "Lindsay, cover me. Sherlock, keep your eyes peeled in case that thing bolts."
Lindsay grabbed his hood and held him back from the wall. "And why are you the one going up?"
"Because I want Sherlock's eyes down here where he'll have the best view of the hall and I want you down here where you're sure of a good shot when I flush it out." She was still frowning at him. He cocked his head at her stubbornly. "Don't make me pull rank.
It gained a smile, but Sherlock rolled his eyes. "She's a faster climber. You're a better shot. Lovejoy should go up and you should cover her."
"We don't know what we're facing up there," John protested staunchly.
"Of course we do – roughly," Sherlock said, shrugging. "Six-limbed bear-like creature with a stinger that delivers pain-inducing venom."
"And you think I should just let someone else face that?"
Lindsay had already edged around him and climbed several stones before he could get more than a garbled protest out. She grinned down at him. "Not your decision to make."
John tightened his jaw over several curses before settling on a simple, "Be careful."
Lindsay laughed. "If I don't, you owe me a dramatic rescue."
John did not reciprocate the laughter. "Not a favor I plan on repaying in kind."
Lindsay grinned and scrambled several feet higher. John pulled his wand back out almost savagely, feeling his body tighten into battle stance. Sherlock, by contrast, had relaxed to the point of limpness, hands sagging into his pockets and shoulders slumped. His eyes were scanning the ceiling with an intensity John could recognize, but the sigh he released made John's hackles rise.
"Bored?" he snapped.
"Yes, actually," Sherlock said, not breaking his scan of the ceiling. Lindsay had reached the blue sky and was climbing through it beyond their range of vision. "This isn't my idea of a rousing good time."
"Lovejoy, report!" John called anxiously, then wheeled to face Sherlock, spitting out the words in rapidfire rhythm. "So sorry chasing a bloody monster around isn't intellectually stimulating enough for you. Maybe it'll challenge you to some sort of Arithmancy duel when we catch up with it. Lovejoy!"
"No sign of it," came her voice. "Just rafters."
"I want reports every fi-"
John's instruction was cut off by a ragged cry from above and a brilliant red flash illuminated the ceiling. The blue disappeared, showing the matrix of rafters that hid above it, and the small figure of a Gryffindor clinging to a beam above the Ravenclaw table, wand pointed to her left. The light died, but there was a screech from above that certainly wasn't human.
"Got it!" Lindsay shouted down a split-second before a second bolt of red revealed a large creature scrabbling at the rafter just forward and left from Lindsay. The body of a house elf was clutched in one of its right limbs, and it was swiping angrily at her with both of its left. Lindsay swore and sent another Stunner at it.
"Don't muck about. Just use the Killing Curse!" John shouted, pointing his own wand even as the blue sky obstructed his view.
Sherlock aimed his wand at the spot the creature had been and muttered something under his breath. There was a jet of blue light, and the sound of a rafter cracking. A shouted spell that ricocheted off two walls above them. The creature was revealed scrambling onto another rafter from the one Sherlock had cracked. John spared a millisecond to marvel that Sherlock had pinpointed the correct rafter without being able to see it, then focused on Lindsay, whose third Stunner revealed she was backing away from the creature as quickly as possible.
"Just kill it!" John shouted. "Stunners aren't working!"
Another flash of light, this one purple, gave John a split second to aim. His Killing Curse blew into the radiant sky and smashed into the wood where the creature had been moments before. It was nowhere to be seen. The ceiling went blue again.
"Lindsay?" John shouted. "Where is it?"
"It's on the rafter with her," Sherlock said calmly, dashing down the aisle to be more directly under the fracas.
John swore. "Lovejoy, just jump!"
She obliged, barely giving him time to cast impervioscurrsus to break her fall. She righted herself in a moment, wand at the ready.
"Did it get you?" John asked, breaking his scan of the ceiling only long enough to ascertain there were no bleeding injuries.
"No, I never let it get close enough," Lindsay said, slightly breathless. "It's bigger than I expected."
The doors burst open and Flitwick, McGonagall, and the Doctor ran in.
"Where?" the Doctor shouted, immediately following their gazes up.
"Somewhere on the other side of the sky," John replied, trying his best not to think of how ridiculous that sounded.
Flitwick drew his wand and drew a complicated design in the air, muttering unintelligibly. The blue lifted, revealing the rafters above and the damage the students had already inflicted, but no creature. The professors instinctively spread out, Flitwick and the Doctor each heading to the corners of the room, while McGonagall moved forward down the center aisle. John nudged Sherlock and Lindsay and indicated that they should move to the forward corners, positioning himself on the same aisle as McGonagall. She had her wand raised and waved it in an impressive arc.
"Revelio!"