“Silence!” snarled Snape. “Well, well, well, I never thought I’d meet a third-year class who wouldn’t even recognize a werewolf when they saw one. I shall make a point of informing Professor Dumbledore how very behind you all are . . . ”

“Please, sir,” said Hermione, whose hand was still in the air, “the werewolf differs from the true wolf in several small ways. The snout of the werewolf—”

“That is the second time you have spoken out of turn, Miss Granger,” said Snape coolly. “Five more points from Gryffindor for being an insufferable know-it-all.”

Hermione went very red, put down her hand, and stared at the floor with her eyes full of tears. It was a mark of how much the class loathed Snape that they were all glaring at him, because every one of them had called Hermione a know-it-all at least once, and Ron, who told Hermione she was a know-it-all at least twice a week, said loudly, “You asked us a question and she knows the answer! Why ask if you don’t want to be told?”

The class knew instantly he’d gone too far. Snape advanced on Ron slowly, and the room held its breath.

“Detention, Weasley,” Snape said silkily, his face very close to Ron’s. “And if I ever hear you criticize the way I teach a class again, you will be very sorry indeed.”

No one made a sound throughout the rest of the lesson. They sat and made notes on werewolves from the textbook, while Snape prowled up and down the rows of desks, examining the work they had been doing with Professor Lupin.

“Very poorly explained . . . That is incorrect, the kappa is more commonly found in Mongolia . . . Professor Lupin gave this eight out of ten? I wouldn’t have given it three . . . ”

When the bell rang at last, Snape held them back.

“You will each write an essay, to be handed in to me, on the ways you recognize and kill werewolves. I want two rolls of parchment on the subject, and I want them by Monday morning. It is time somebody took this class in hand. Weasley, stay behind, we need to arrange your detention.”

Harry and Hermione left the room with the rest of the class, who waited until they were well out of earshot, then burst into a furious tirade about Snape.

“Snape’s never been like this with any of our other Defense Against the Dark Arts teachers, even if he did want the job,” Harry said to Hermione. “Why’s he got it in for Lupin? D’you think this is all because of the boggart?”

“I don’t know,” said Hermione pensively. “But I really hope Professor Lupin gets better soon . . . ”

Ron caught up with them five minutes later, in a towering rage.