There's kind of a giant twist in here. I can't really properly gauge how much of a twist it is, since I've been thinking of it for ages so it's obvious to me. Anyways I hope you enjoy!
Actually it's more of a reveal than a twist.
But you'll be the judge of that.
"It's broken out!" Sherlock shouts towards the group of professors gathered at the main hall. They're busy herding the students inside. I guess in the panic they've decided it'd be safer if the students all stayed within eyeshot. "Whatever it was that ruined the fat lady made an absolute wreck of my office and broke out through the window." He huffs, angry and a little bit breathless from the jog down.
Snape looks at us suspiciously. "Your office?" Sherlock pointedly ignores him.
"Did you see it?" Mcgonagall asks, with an authoritative air. "The fat lady can't be considered reliable at present. She is quite... distressed."
"May have been some sort of big... dog? Going by the pawprints?" I suggest with a distinct feeling of deja vu at the words. "Was it possible that some kid... I don't know let a dog loose?" I give the most obvious explanation just to start the ball rolling.
"Typical. Leave it to wizards to fly into a panic over a loose pet." Sherlock growls bitterly.
"The grim! It's come!" A rather mad looking professor mumbles frantically. "It's the grim!"
"We can't be sure of anything yet." Mcgonagall sighs, rolling her eyes at the frazzled woman. "It'll be safer to keep the children under watch at least until daylight."
Sherlock grins, a precursor to an Anderson-worthy mocking session. I brace myself, ready to reign him in before he gives someone a breakdown. "Of course, brilliant idea. If it is a serial killer, you've got all the prime targets grouped up in one spot for Sirius's convenience. It can be so hard to pick them off one by one. How considerate of you to shorten the job for him. And if it isn't, you've got all of the little youngsters terrified out of their wits. Because can it really be considered Halloween if you're not terrified for your life?"
Snape steps forward greasily. "Oh and I suppose you have got a better idea, do you?"
This'll be interesting. I wonder what scathing comeback he'll come up with this time. It baffles me how he manages never to repeat one. "I bet John could come up with a better idea." What.
Snape turns his sharp, pointed nose toward me. God, he could peck an eye out with that thing. On topic, Watson. You need to find a better way to protect the students from a serial killer than packing all of them in one room. Granted, the serial killer is under our bed but... Thinkthinkthinkthink OH... maybe...
"Uh... You could... take all of the students back to their dormitories. But leave the blankets and pillows and things here. Keep...uh... Hagrid guarding the main hall and have the rest of the professors patrolling outside the common rooms. If there's anybody out there, which there may not be anyways, it doesn't matter if they assume the children are in one place or spread out. They're bound to be caught if they come back." That was... not bad? Definitely plausible. Sherlock nods at me subtly, signifying that I've done something right.
A wrinkled hand lands on my shoulder. "Who's a clever kitty!" Dumbledore's eyes glitter as Mcgonagall nods approvingly, although still a bit miffed from Sherlock's onslaught. Snape looks as if he's hoping fire will rain down from the painted sky and kill us all. Trelawney is... chanting something.
"We'll send the children back to their beds straight away." Mcgonagall sighs.
"Now if you'll excuse us, I've got to survey the full extent of the damage done to my office." Sherlock sweeps away without another word and I follow after.
It slowly becomes more and more obvious that we we're being followed the closer we get to the office. At first, the scuffling of shoes could've easily been mistaken for the students heading back to their dormitories. But the farther we go, the heavier their breathing gets.
"Sherlock?" I whisper, barely louder than a breath.
"Yes." He answers the question I never actually asked. He rolls his eyes at the sloppy work of whoever's trailing us. We continue on, ignoring our shadow.
Sherlock tugs me off our normal route. Just round a corner and into a nook behind a suit of armor. Out to catch our shadow, then. The clumsily hesitant footsteps draw nearer and nearer and finally Snape passes us. Sherlock lightly steps out of our hiding spot, silently creeping up on Snape. I stay in the nook and try to stifle my laughter. I'm not as lightfooted as Sherlock. I'd be sure to give him away.
"Out for a walk?" Snape just about shits himself in shock. "Or are you trying to catch me in the act of harboring a fugitive." He says with a cold, mocking smile.
"So you admit to it." Snape pulls himself together, turning swiftly on his heel. I lean against the wall and observe. The tension between them is so thick, I could walk between them and do a jig and neither of them would notice.
He scoffs, the smile dropping into exasperation. "What do you believe my motivation would be for providing aid to a serial killer? To let him loose on the school at a later date to pick off the children one by one for my own amusement? To have him act as a decoy when I do so myself?"
"I know you were... associated with him."
"Oh please. Is that all you've got to go on? I was engaged in a physical relationship with him over a decade ago so I must be in love with him and thus desperate to help him carry out whatever murderous plans he may have?" Wha-wait. I couldn't have heard him right. 'Physical relationship'? "You may be cowardly, greasy and worth less than the scum on my shoes, but I never thought you'd be that stupid."
"Hardly. When have you ever been capable of that?"
"Murder?"
"Love." Sherlock doesn't respond in action or words. He just gives off a distinct aura of eye-rolling. Meanwhile Snape circles him like an oversized vulture. "I believe the two of you are plotting something. That much is obvious." He comes to a stop in front of Sherlock. "As for motivation? We all know Black wants to finish what he started. But you. I think you're involved for the same reason you've ever done anything. Becau-"
"Because I'm bored. Yes yes of course. Now if I may point out the fact that I do get bored easily and there is nothing more boring than you coming to only the most obvious conclusions. So if you have a point, could you please get to it before I yawn and kill us all?"
"My point is, you're up to something."
"Ooh. Scared?" He grins devilishly. He starts reciprocating the circling. Is this some sort... archnemesis ettiquette? Like shaking hands? "I wonder what frightens you more? The thought that I'm as much of a monster as the rumours say... or the possibility that I'm just... as human... as you." With the end of the sentence, he uses the momentum he's built by using Snape as a maypole and launches down the torch lit hallway.
"Come along John." I jog after his retreating silhouette, cursing his flair for dramaticism with every step.
"Physical relationship?" I ask after Snape is well out of ear-shot.
"You didn't actually believe Mycroft's implications, did you?" He sighs in his usual 'Mycroft is too clueless to know how clueless he is' tone of voice. "Believe it or not I do have functioning reproductive organs." He talks like that and still he wonders why I'm so shocked.
"With the muddy dogman hiding under our bed."
"Don't be jealous. It didn't mean anything." Like that's what I care about. I just now learn that my mechanical flatmate slept with the convicted serial killer that walked through our door on all fours an hour ago and he assumes my issue is jealousy. "We hardly spoke to each other if we could help it."
"Is... is that why we're here? Because you owe your ex-boyfriend a favor?" Oh god, if that is the case I'm calling up Mrs. Hudson and he will never hear the end of it.
"Never. My. Boyfriend." He growled, glaring up at the chattering portraits. "We weren't even friends. He was just a rebel trying to piss off his parents and I was a stupid hormonal teenager desperate to feel things."
"So you do owe him a favour."
"No. We're here because wizards are idiots." He rumbled, swinging open the door to the office.