Even after three more classes and two more meals, James was still fuming about the Potions class incident when the boys returned to their dormitory that night. "Those inbred Slytherin gits," he growled, pacing back and forth across the room. "How did the blond one know that charm, anyway? We haven't even had our first Charms class yet!"
"It was the Levitation Charm," Remus told him. "Wingardium Leviosa. It's one of the first ones listed in our textbook."
"Oh, even better," said Sirius. "Nerdy Slytherin gits who start reading their books before classes even start."
"I started reading my books as soon as I got them," Remus murmured, though if he was offended by Sirius's comment he didn't show it.
"Well," James said, "by the end of the night, they're going to regret ever crossing James Fleamont Potter."
"Fleamont?" Sirius asked, hardly suppressing a laugh.
"It's my dad's name, all right?" Fleamont Potter wasn't too fond of his name either, which made James wonder why he had decided to grace his only son with it.
"What exactly are you planning to do?" Remus wondered. "You don't even know the Slytherins' names."
"Well, we know Snivellus," Sirius put in. "And one of them's called Michael Avery; he was Sorted right before me. Dunno about the one who used the Charm, though."
"Doesn't matter," said James. "We'll just punish the lot of them." Reaching into his trunk, he pulled out a little box marked with a cockroach on its side.
Sirius's eyes widened at the sight of it. "Is that what I think it is?"
James grinned. "Yep."
"Wait, what is it?" Peter asked.
"A Multiplying Roach," James explained. "Ordered it from Zonko's. As soon as you turn it on, the number of roaches doubles every five seconds. And they can squeeze into any space—even the Slytherin Common Room."
Sirius clapped his hands together. "Brilliant, James. I'm in."
"I'm not," said Remus. "It won't work; you're just going to get caught and thrown in detention."
"Not if we use this." James reached again into his trunk and took out a cloak made of shimmering, silvery fabric. He wrapped it around his shoulders, and his body disappeared out from under him.
All three of his roommates let out loud gasps. Peter tumbled off his bed with a yelp.
"It's an Invisibility Cloak," James told them. "My dad's. I nicked it from his office the day before we came here."
"I didn't even know those existed," Peter breathed, his voice an octave higher than it was before.
"That is the coolest thing I have ever seen, mate," Sirius told him. "We can go anywhere with that."
"So, now are you in?" James asked Remus and Peter. "There's room for all four of us under this thing."
But Remus still shook his head, the corner of his mouth twisting up in a smile. "You seem to have it all planned out already, anyway." He pulled out a copy of Hogwarts, A History, a book not even on the first years' required reading list, and began sifting through it.
"Um…I think I'll stay, too," said Peter. "I would just slow you down if I came." He was probably right about that, James thought. Between a foaming potion and three spell mishaps on their first day, one of which had almost taken Sirius's ear off, James wasn't sure Peter would be the best person to tag along on his mission. He would've liked Remus to come, though; if he already knew some spells, he could come in handy if they were in a bind.
"Oh, fine, you cowards," Sirius said, though he sounded more amused than angry. "James and I will go alone. But no ratting us out to Gideon, got it?"
Peter shook his head vigorously, and Remus sealed his lips without looking up from his book.
"Good." Sirius climbed under the Invisibility Cloak, and James adjusted it so that it covered both of them completely. He stuffed the cockroach box into his pocket, and they were off.
The Gryffindor common room was nearly empty; no one was studying or doing homework after one day of class. The boys pushed their way out the door past the sleeping entrance portrait—the Fat Lady, she was called—and into the hall outside.
The lights were dim, with only a few sparse candles flickering weakly throughout the empty corridors. It was after hours, a time when the students were strictly forbidden from leaving their dormitories and common rooms without permission. There could be prefects or professors patrolling the halls, but James had been warned earlier by a couple of second years to mostly worry about the Hogwarts caretaker, an old man named Filch, and his creepy cat Mrs. Norris.
"The Slytherin common room's in the dungeons, right?" Sirius whispered in James's ear.
James nodded under the cloak. "Yeah. I saw the entrance on our way to Potions class."
The two of them had a hard enough time just reaching the dungeons; they knew they had to head downward, which would have been simple enough if the staircases didn't move around or change location all the time. Finally they reached the ground floor of Hogwarts and found the steps into the dungeons, stone and reliably stationary.
"Here." James led Sirius over to a door carved out of the dungeon wall, the entrance to the Slytherin common room. Pictures of serpents twisted their way around the door, eyeing the seemingly-empty hall suspiciously.
The boys knelt down, and James shook the Multiplying Roach out of its box. "All right, little bug," he said, pressing the roach's left wing to activate it. "Go scare some Slytherins." He placed the roach on the ground and directed it towards the common room. It began to scurry along, another roach breaking off from it a few seconds later, then another. By the time the roaches reached the door and began to wedge their way through the cracks, there were more than fifty of them.
"Any second now," James breathed as the roaches vanished inside. He and Sirius held their breath, squeezing each other's knees, until a girl's frightened shriek rang out from inside the common room. James buried his face in Sirius's shoulder to keep from laughing as the single shriek grew into a chorus of panicked yelling, cursing, and screaming.
"Oh, this is fantastic," Sirius whispered, a hand over his mouth. "I hope Lucius and Narcissa are in there."
Mrow. James jumped when he heard the sudden noise behind him, and twisted around to find a yellow-eyed, bony cat glaring right at them, swishing her tail back and forth angrily. James was sure she could see them, even under the cloak.
"Sirius." He nudged his roommate frantically. "I think that's Mrs. Norris. The caretaker's cat."
"I think you're right," said Sirius nervously. "If she sees someone misbehaving, she runs right off to him to get them in trouble."
Sure enough, the cat turned tail and vanished down another hallway. "And there she goes," James said.
"Okay, let's get out of here." The boys jumped up and headed quickly for the stairs out of the dungeons. Once outside, they tore down a hall at random, having no idea where they were going. James's shoe caught on the hem of the cloak, and it was ripped off of him and Sirius, leaving them visible again.
"Bollocks." James spun around to pick up the cloak, but before he could throw it back on a figure jumped out from around a corner, the lantern in his hand lighting up his old, cruel face. Beside him trotted the yellow-eyed cat, looking almost smug.
James and Sirius stood still as the man rushed over to them, his mouth twisted in a yellow-toothed snarl. "Only one day of class, and we already have students prowling about the castle," he growled. "I wonder, could the two of you have anything to do with the ruckus in the Slytherin common room?"
"Oh, I don't think the Slytherins need anyone's help to cause a ruckus," replied Sirius. "Have you met them?"
The man—Filch—was now close enough for them to taste his moldy breath. He held his lantern up to each of their faces, studying them. "Ah, first years, I see. What are your names?"
"I'm Snivellus," said Sirius, "and this here is Fleamont." James bit back a laugh.
"I don't think so, Mr. Black," said Filch, ripping the laugh from James's lips. "I keep track of all the students who come through this school, you see. Especially the Blacks. Your family has given me lots of trouble, and I can see you're shaping up to be no different."
"Well, that wasn't very nice," Sirius said reproachfully. "Asking our names when you already know them. You deserved to get a wrong answer for that." James was impressed by how cocky Sirius was in the face of someone who had the power to punish him however he liked; then again, James could guess that he'd been in the same situation many times before with his family. It made James feel cockier, too.
Filch directed his light down to James's arms, currently holding the Invisibility Cloak tightly behind his back. "What have you got there, Mr. Potter?" he asked. "Hiding something?"
Very reluctantly, James showed Filch the cloak, not knowing what else he could do. Filch snatched it from his hands and examined it with narrowed eyes. "What is this?" he demanded. "A cloak?"
"My parents got it for me at Madam Malkin's," James told him. "It's rubbish, though. Silver isn't really my color." Hopefully Filch wouldn't try it on, and find out how very much not-rubbish the cloak was.
"Well, seeing how eager you were to keep this from me, I think I'll be taking it just in case." And Filch slung the cloak over his shoulder. Before James could get too upset, Sirius shot him a look that said, We're going to get it back. James nodded.
"And you boys," Filch continued, "have the honor of being given the very first detentions of the year."
James and Sirius's high-five at this statement did nothing to improve the expression on Filch's face.
