“What’s that?” said Harry.
“Another boggart,” said Lupin, stripping off his cloak. “I’ve been combing the castle ever since Tuesday, and very luckily, I found this one lurking inside Mr. Filch’s filing cabinet. It’s the nearest we’ll get to a real dementor. The boggart will turn into a dementor when he sees you, so we’ll be able to practice on him. I can store him in my office when we’re not using him; there’s a cupboard under my desk he’ll like.”
“Okay,” said Harry, trying to sound as though he wasn’t apprehensive at all and merely glad that Lupin had found such a good substitute for a real dementor.
“So . . .” Professor Lupin had taken out his own wand, and indicated that Harry should do the same. “The spell I am going to try and teach you is highly advanced magic, Harry — well beyond Ordinary Wizarding Level. It is called the Patronus Charm.”
“How does it work?” said Harry nervously.
“Well, when it works correctly, it conjures up a Patronus,” said Lupin, “which is a kind of anti-dementor — a guardian that acts as a shield between you and the dementor.”
Harry had a sudden vision of himself crouching behind a Hagrid-sized figure holding a large club. Professor Lupin continued, “The Patronus is a kind of positive force, a projection of the very things that the dementor feeds upon — hope, happiness, the desire to survive — but it cannot feel despair, as real humans can, so the dementors can’t hurt it. But I must warn you, Harry, that the charm might be too advanced for you. Many qualified wizards have difficulty with it.”
“What does a Patronus look like?” said Harry curiously.
“Each one is unique to the wizard who conjures it.”
“And how do you conjure it?”
“With an incantation, which will work only if you are concentrating, with all your might, on a single, very happy memory.”
Harry cast his mind about for a happy memory. Certainly, nothing that had happened to him at the Dursleys’ was going to do. Finally, he settled on the moment when he had first ridden a broomstick.
“Right,” he said, trying to recall as exactly as possible the wonderful, soaring sensation of his stomach.
“The incantation is this —” Lupin cleared his throat. “Expecto Patronum!”
“Expecto Patronum,” Harry repeated under his breath, “Expecto Patronum.”
“Concentrating hard on your happy memory?”
“Oh — yeah —” said Harry, quickly forcing his thoughts back to that first broom ride. “Expecto Patrono — no, Patronum — sorry — Expecto Patronum, Expecto Patronum —”
Something whooshed suddenly out of the end of his wand; it looked like a wisp of silvery gas.
“Did you see that?” said Harry excitedly. “Something happened!”
“Very good,” said Lupin, smiling. “Right, then — ready to try it on a dementor?”
“Yes,” Harry said, gripping his wand very tightly, and moving into the middle of the deserted classroom. He tried to keep his mind on flying, but something else kept intruding. . . . Any second now, he might hear his mother again . . . but he shouldn’t think that, or he would hear her again, and he didn’t want to . . . or did he?
Lupin grasped the lid of the packing case and pulled.
A dementor rose slowly from the box, its hooded face turned toward Harry, one glistening, scabbed hand gripping its cloak. The lamps around the classroom flickered and went out. The dementor stepped from the box and started to sweep silently toward Harry, drawing a deep, rattling breath. A wave of piercing cold broke over him —
“Expecto Patronum!” Harry yelled. “Expecto Patronum! Expecto —”
But the classroom and the dementor were dissolving. . . . Harry was falling again through thick white fog, and his mother’s voice was louder than ever, echoing inside his head — “Not Harry! Not Harry! Please — I’ll do anything —”
“Stand aside. Stand aside, girl!”
“Harry!”
Harry jerked back to life. He was lying flat on his back on the floor. The classroom lamps were alight again. He didn’t have to ask what had happened.
“Sorry,” he muttered, sitting up and feeling cold sweat trickling down behind his glasses.
“Are you all right?” said Lupin.
“Yes . . .” Harry pulled himself up on one of the desks and leaned against it.
“Here —” Lupin handed him a Chocolate Frog. “Eat this before we try again. I didn’t expect you to do it your first time; in fact, I would have been astounded if you had.”
“It’s getting worse,” Harry muttered, biting off the Frog’s head. “I could hear her louder that time — and him — Voldemort —”
Lupin looked paler than usual.
“Harry, if you don’t want to continue, I will more than understand —”
“I do!” said Harry fiercely, stuffing the rest of the Chocolate Frog into his mouth. “I’ve got to! What if the dementors turn up at our match against Ravenclaw? I can’t afford to fall off again. If we lose this game we’ve lost the Quidditch Cup!”
“All right then . . . ,” said Lupin. “You might want to select another memory, a happy memory, I mean, to concentrate on. . . . That one doesn’t seem to have been strong enough. . . .”
Harry thought hard and decided his feelings when Gryffindor had won the House Championship last year had definitely qualified as very happy. He gripped his wand tightly again and took up his position in the middle of the classroom.
“Ready?” said Lupin, gripping the box lid.
“Ready,” said Harry, trying hard to fill his head with happy thoughts about Gryffindor winning, and not dark thoughts about what was going to happen when the box opened.
“Go!” said Lupin, pulling off the lid. The room went icily cold and dark once more. The dementor glided forward, drawing its breath; one rotting hand was extending toward Harry —