Use it well.
Suddenly, Harry felt wide-awake. The whole of Hogwarts was open to him in this Cloak. Excitement flooded through him as he stood there in the dark and silence. He could go anywhere in this, anywhere, and Filch would never know.
Ron grunted in his sleep. Should Harry wake him? Something held him back — his father’s Cloak — he felt that this time — the first time — he wanted to use it alone.
He crept out of the dormitory, down the stairs, across the common room, and climbed through the portrait hole.
“Who’s there?” squawked the Fat Lady. Harry said nothing. He walked quickly down the corridor.
Where should he go? He stopped, his heart racing, and thought. And then it came to him. The Restricted Section in the library. He’d be able to read as long as he liked, as long as it took to find out who Flamel was. He set off, drawing the Invisibility Cloak tight around him as he walked.
The library was pitch-black and very eerie. Harry lit a lamp to see his way along the rows of books. The lamp looked as if it was floating along in midair, and even though Harry could feel his arm supporting it, the sight gave him the creeps.
The Restricted Section was right at the back of the library. Stepping carefully over the rope that separated these books from the rest of the library, he held up his lamp to read the titles.
They didn’t tell him much. Their peeling, faded gold letters spelled words in languages Harry couldn’t understand. Some had no title at all. One book had a dark stain on it that looked horribly like blood. The hairs on the back of Harry’s neck prickled. Maybe he was imagining it, maybe not, but he thought a faint whispering was coming from the books, as though they knew someone was there who shouldn’t be.
He had to start somewhere. Setting the lamp down carefully on the floor, he looked along the bottom shelf for an interesting-looking book. A large black and silver volume caught his eye. He pulled it out with difficulty, because it was very heavy, and, balancing it on his knee, let it fall open.
A piercing, bloodcurdling shriek split the silence — the book was screaming! Harry snapped it shut, but the shriek went on and on, one high, unbroken, earsplitting note. He stumbled backward and knocked over his lamp, which went out at once. Panicking, he heard footsteps coming down the corridor outside — stuffing the shrieking book back on the shelf, he ran for it. He passed Filch in the doorway; Filch’s pale, wild eyes looked straight through him, and Harry slipped under Filch’s outstretched arm and streaked off up the corridor, the book’s shrieks still ringing in his ears.
He came to a sudden halt in front of a tall suit of armor. He had been so busy getting away from the library, he hadn’t paid attention to where he was going. Perhaps because it was dark, he didn’t recognize where he was at all. There was a suit of armor near the kitchens, he knew, but he must be five floors above there.
“You asked me to come directly to you, Professor, if anyone was wandering around at night, and somebody’s been in the library — Restricted Section.”
Harry felt the blood drain out of his face. Wherever he was, Filch must know a shortcut, because his soft, greasy voice was getting nearer, and to his horror, it was Snape who replied, “The Restricted Section? Well, they can’t be far, we’ll catch them.”
Harry stood rooted to the spot as Filch and Snape came around the corner ahead. They couldn’t see him, of course, but it was a narrow corridor and if they came much nearer they’d knock right into him — the Cloak didn’t stop him from being solid.
He backed away as quietly as he could. A door stood ajar to his left. It was his only hope. He squeezed through it, holding his breath, trying not to move it, and to his relief he managed to get inside the room without their noticing anything. They walked straight past, and Harry leaned against the wall, breathing deeply, listening to their footsteps dying away. That had been close, very close. It was a few seconds before he noticed anything about the room he had hidden in.
It looked like an unused classroom. The dark shapes of desks and chairs were piled against the walls, and there was an upturned wastepaper basket — but propped against the wall facing him was something that didn’t look as if it belonged there, something that looked as if someone had just put it there to keep it out of the way.
It was a magnificent mirror, as high as the ceiling, with an ornate gold frame, standing on two clawed feet. There was an inscription carved around the top: Erised stra ehru oyt ube cafru oyt on wohsi.
His panic fading now that there was no sound of Filch and Snape, Harry moved nearer to the mirror, wanting to look at himself but see no reflection again. He stepped in front of it.
He had to clap his hands to his mouth to stop himself from screaming. He whirled around. His heart was pounding far more furiously than when the book had screamed — for he had seen not only himself in the mirror, but a whole crowd of people standing right behind him.
But the room was empty. Breathing very fast, he turned slowly back to the mirror.
There he was, reflected in it, white and scared-looking, and there, reflected behind him, were at least ten others. Harry looked over his shoulder — but still, no one was there. Or were they all invisible, too? Was he in fact in a room full of invisible people and this mirror’s trick was that it reflected them, invisible or not?