While the young wizards deep beneath the Castle were still cheering...
The Defense Against Dark Magic Office.
Dry firewood burned fiercely, crackling and popping.
Sirius sprawled gracelessly in an armchair. His shirt collar hung open, and his leather shoes rested brazenly on the edge of the coffee table. He lazily swirled a glass of whisky in his hand, the ice clinking against its sides.
"Douglas, those trials you set up down below back in your student days-are they really as harmless as you say?"
"Old Filch has been running to the Academic Affairs Office every day lately, going on and on about how those kids are practically tearing the dungeons apart. He's actually quite happy, though. Says he's cleared out plenty of old things that had been piling up for decades."
Douglas did not even raise his head. He was marking the seventh years' monthly exam papers.
"What? Didn't you lot get up to things in the dungeons when you were students?"
Sirius took a sip and gave a disdainful snort.
"We always headed outside. Who burrowed underground like you lot? Oh-ho, right, I forgot. You were a Hufflepuff. You probably led the other three astray."
Only then did Douglas lift his eyes and give him an eye roll.
"Why aren't you busy keeping an eye on the company's new project? What brings you here in the middle of the night to pry into the students' trials?"
As though he had suffered the greatest insult imaginable, Sirius clutched his chest, putting on an outrageously aggrieved expression. His voice rose as he set his glass on the coffee table with a bang and sat upright.
"Merlin's banana, get your facts straight. I'm the bona fide director of the Hogwarts Academic Affairs Office. Owning Marauders Power Company is just my sideline. Besides..."