On the last night of their three weeks of detention, Filch had James and Sirius clean out his own office. "I don't want to see a speck of dust in here when you're done, or you'll be coming back tomorrow night to finish the job," Filch threatened. "And if I find anything a hair out of place, I'll add another week of detentions."

James and Sirius gave each other exasperated looks. They'd already had to polish the school trophies and candelabras, sort out Slughorn's potion stocks, prune Shrivelfigs, and all sorts of other unpleasant tasks throughout the castle. It was more fun with James, of course, who always found ways for them to entertain themselves while they worked, but Sirius was more than ready to be done with it all.

"I want all my files organized, all my chains oiled, and all surfaces wiped down. Got it?"

"Got it," Sirius confirmed, resisting the urge to say something smart. Filch nodded, and locked them inside his office.

Sirius sighed as he took in the room. Its filing cabinets were overflowing with papers and folders sticking out at haphazard angles, and dusty shackles and manacles hung down from the walls. By the looks of them, they hadn't been used in ages, which Sirius supposed was somewhat relieving.

"All right," James said, cracking his knuckles. "I'll start with sorting out the files, and you can deal with the medieval torture devices. Sound good?"

"Fine with me." Grabbing some wipes and a bottle of linseed oil, Sirius climbed on top of Filch's desk and got to work scrubbing and oiling.

"Hey, look at this." James held up a folder on which the names James Potter and Sirius Black had been scrawled. "We've got our own folder, Sirius." He took out the one slip of paper inside of it, detailing the prank they'd pulled on the Slytherins.

"What an honor," Sirius said with a laugh. "We'll have to be sure it's filled by the time we leave here."

"Oh, I think we can fill a whole cabinet by the time we leave," James replied. "That's my goal, at least."

"Mine, too." Sirius finished with the last of the shackles, then hopped down to help James with the files.

One of the first folders he came across was labelled Orion Black. It was stuffed with files, some of which looked to have been spattered with blood. "Looks like my father was a bit of trouble here, too," Sirius said, showing James the folder.

"That's your dad?" James flipped through its papers with widened eyes. "Blimey. I should look for my parents in here, too. I wonder what kind of things they got into in school."

Sirius took back his father's folder, tucking the papers neatly inside of it. "I wonder if he'd be proud I'm following in his footsteps," Sirius said. "But we're in here for messing with the Slytherins, so probably not."

It was another few minutes before James spoke up again, and when he did, his voice was quieter and more careful. "Hey, Sirius?" he asked. "I know you don't like to talk much about your family, but…what happened with them? I know they're crazy pure-blood gits and all, but how come you're not one, too?"

Oh, Merlin. Had Sirius ever been like his parents? Had he ever liked them, loved them, even, the way sons were supposed to? He thought for a long time before answering. "Because of my brother Reggie, I think."

James blinked at him; Sirius realized he'd never mentioned his brother before. "My mum started picking on him almost before he could walk. Thought he was too slow, and didn't show enough signs of magic. And, well, he was my little brother. I couldn't let her get away with it. So I stood up to her, and soon enough she made me her target instead."

"Ouch," James said with a wince. "I'm sorry, mate."

Sirius shook his head. "I'm not; who knows how I would've turned out if my parents actually liked me. I'd probably be mates with Snivellus instead." Both boys shuddered at the thought. "Now Reggie's just like the rest of them, all ready to join up with the Slytherins. I just feel bad for him, really."

The boys cleaned in silence for a while, Sirius's words hanging over their heads like another layer of dust. Then, when he was scrubbing beneath Filch's desk, James exclaimed that he'd found a locked box pressed up against the wall. "Confiscated Items," he read excitedly, pulling it out. "D'you reckon my cloak's in here?"

"Probably," Sirius said. "But I'm sure Filch has put some enchantment over it so it can't be opened."

"Well, we know the charm," said James. "Can't hurt to try, can it?" He waved his wand at the lock and muttered, "Alohomora."

The box sprang open; James shot Sirius a satisfied glance. Sirius raised his eyebrows, surprised Filch hadn't used any magic to keep people out of the things he'd filched.

"Aha," James cried, pulling out his Invisibility Cloak. "Thank Merlin. I was missing this."

"What else is in there?" Sirius wondered, leaning in over the box. It was filled with Zonko's products, Auto-Answer Quills, bewitched parchment, and plenty of things Sirius had never seen before. He pulled out a Fanged Frisbee. "I'd say we stock up on these," he said; "they're perfect for pissing people off in the halls."

James held out a hand to stop him. "If we take everything in here, Filch will realize and he'll know it was us. My cloak's practically invisible anyway, but we can't take the whole box."

"Oh, come on," Sirius said. "We bested Filch with Alohomora. Are you really that afraid of him?"

"Not afraid," James said defensively. "I'm just tired of spending every night in detention, that's all. Besides, with my cloak, we can find a way into Hogsmeade and get things from Zonko's ourselves."

Sirius tilted his head. "Promise?"

"I promise," James said. "The Invisibility Cloak's worth a thousand Fanged Frisbees, trust me."

"Fine," Sirius sighed, throwing the Frisbee back in. "I guess you're right. I don't think I could stand another night of polishing old Quidditch trophies."

So the boys locked the box back up and returned to work, James stuffing the Invisibility Cloak deep inside the pocket of his coat.