Harry skidded to a halt outside the Defense Against the Dark Arts classroom, pulled the door open, and dashed inside.

“Sorry I’m late, Professor Lupin, I—”

But it wasn’t Professor Lupin who looked up at him from the teacher’s desk; it was Snape.

“This lesson began ten minutes ago, Potter, so I think we’ll make it ten points from Gryffindor. Sit down.”

But Harry didn’t move.

“Where’s Professor Lupin?” he said.

“He says he is feeling too ill to teach today,” said Snape with a twisted smile. “I believe I told you to sit down?”

But Harry stayed where he was.

“What’s wrong with him?”

Snape’s black eyes glittered.

“Nothing life-threatening,” he said, looking as though he wished it were. “Five more points from Gryffindor, and if I have to ask you to sit down again, it will be fifty.”

Harry walked slowly to his seat and sat down. Snape looked around at the class.

“As I was saying before Potter interrupted, Professor Lupin has not left any record of the topics you have covered so far—”

“Please, sir, we’ve done boggarts, Red Caps, kappas, and grindylows,” said Hermione quickly, “and we’re just about to start—”

“Be quiet,” said Snape coldly. “I did not ask for information. I was merely commenting on Professor Lupin’s lack of organization.”

“He’s the best Defense Against the Dark Arts teacher we’ve ever had,” said Dean Thomas boldly, and there was a murmur of agreement from the rest of the class. Snape looked more menacing than ever.

“You are easily satisfied. Lupin is hardly overtaxing you—I would expect first years to be able to deal with Red Caps and grindylows. Today we shall discuss—”

Harry watched him flick through the textbook, to the very back chapter, which he must know they hadn’t covered.

“—werewolves,” said Snape.

“But, sir,” said Hermione, seemingly unable to restrain herself, “we’re not supposed to do werewolves yet, we’re due to start hinkypunks—”

“Miss Granger,” said Snape in a voice of deadly calm, “I was under the impression that I am teaching this lesson, not you. And I am telling you all to turn to page 394.” He glanced around again. “All of you! Now!”

With many bitter sidelong looks and some sullen muttering, the class opened their books.

“Which of you can tell me how we distinguish between the werewolf and the true wolf?” said Snape.

Everyone sat in motionless silence; everyone except Hermione, whose hand, as it so often did, had shot straight into the air.

“Anyone?” Snape said, ignoring Hermione. His twisted smile was back. “Are you telling me that Professor Lupin hasn’t even taught you the basic distinction between—”

“We told you,” said Parvati suddenly, “we haven’t got as far as werewolves yet, we’re still on—”