“I know what I should have done,” said Harry, resting, facedown, on Saucy Tricks for Tricky Sorts. “I should’ve learned to be an Animagus like Sirius.”

An Animagus was a wizard who could transform into an animal.

“Yeah, you could’ve turned into a goldfish any time you wanted!” said Ron.

“Or a frog,” yawned Harry. He was exhausted.

“It takes years to become an Animagus, and then you have to register yourself and everything,” said Hermione vaguely, now squinting down the index of Weird Wizarding Dilemmas and Their Solutions. “Professor McGonagall told us, remember . . . you’ve got to register yourself with the Improper Use of Magic Office . . . what animal you become, and your markings, so you can’t abuse it . . . ”

“Hermione, I was joking,” said Harry wearily. “I know I haven’t got a chance of turning into a frog by tomorrow morning . . . ”

“Oh this is no use,” Hermione said, snapping shut Weird Wizarding Dilemmas. “Who on earth wants to make their nose hair grow into ringlets?”

“I wouldn’t mind,” said Fred Weasley’s voice. “Be a talking point, wouldn’t it?”

Harry, Ron, and Hermione looked up. Fred and George had just emerged from behind some bookshelves.

“What’re you two doing here?” Ron asked.

“Looking for you,” said George. “McGonagall wants you, Ron. And you, Hermione.”

“Why?” said Hermione, looking surprised.

“Dunno . . . she was looking a bit grim, though,” said Fred.

“We’re supposed to take you down to her office,” said George.

Ron and Hermione stared at Harry, who felt his stomach drop. Was Professor McGonagall about to tell Ron and Hermione off? Perhaps she’d noticed how much they were helping him, when he ought to be working out how to do the task alone?

“We’ll meet you back in the common room,” Hermione told Harry as she got up to go with Ron—both of them looked very anxious. “Bring as many of these books as you can, okay?”

“Right,” said Harry uneasily.

By eight o’clock, Madam Pince had extinguished all the lamps and came to chivvy Harry out of the library. Staggering under the weight of as many books as he could carry, Harry returned to the Gryffindor common room, pulled a table into a corner, and continued to search. There was nothing in Madcap Magic for Wacky Warlocks . . . nothing in A Guide to Medieval Sorcery . . . not one mention of underwater exploits in An Anthology of Eighteenth-Century Charms, or in Dreadful Denizens of the Deep, or Powers You Never Knew You Had and What to Do with Them Now You’ve Wised Up.