Harry opened his eyes. He was still in the library; the Invisibility Cloak had slipped off his head as he’d slept, and the side of his face was stuck to the pages of Where There’s a Wand, There’s a Way. He sat up, straightening his glasses, blinking in the bright daylight.

“Harry Potter needs to hurry!” squeaked Dobby. “The second task starts in ten minutes, and Harry Potter—”

“Ten minutes?” Harry croaked. “Ten—ten minutes?”

He looked down at his watch. Dobby was right. It was twenty past nine. A large, dead weight seemed to fall through Harry’s chest into his stomach.

“Hurry, Harry Potter!” squeaked Dobby, plucking at Harry’s sleeve. “You is supposed to be down by the lake with the other champions, sir!”

“It’s too late, Dobby,” Harry said hopelessly. “I’m not doing the task, I don’t know how—”

“Harry Potter will do the task!” squeaked the elf. “Dobby knew Harry had not found the right book, so Dobby did it for him!”

“What?” said Harry. “But you don’t know what the second task is—”

“Dobby knows, sir! Harry Potter has to go into the lake and find his Wheezy—”

“Find my what?”

“—and take his Wheezy back from the merpeople!”

“What’s a Wheezy?”

“Your Wheezy, sir, your Wheezy—Wheezy who is giving Dobby his sweater!”

Dobby plucked at the shrunken maroon sweater he was now wearing over his shorts.

“What?” Harry gasped. “They’ve got . . . they’ve got Ron?”

“The thing Harry Potter will miss most, sir!” squeaked Dobby. “ ‘But past an hour—’ ”

“—‘the prospect’s black,’ ” Harry recited, staring, horror-struck, at the elf. “ ‘Too late, it’s gone, it won’t come back.’ Dobby—what’ve I got to do?”

“You has to eat this, sir!” squeaked the elf, and he put his hand in the pocket of his shorts and drew out a ball of what looked like slimy, grayish-green rat tails. “Right before you go into the lake, sir—gillyweed!”

“What’s it do?” said Harry, staring at the gillyweed.

“It will make Harry Potter breathe underwater, sir!”

“Dobby,” said Harry frantically, “listen—are you sure about this?”

He couldn’t quite forget that the last time Dobby had tried to “help” him, he had ended up with no bones in his right arm.

“Dobby is quite sure, sir!” said the elf earnestly. “Dobby hears things, sir, he is a house-elf, he goes all over the castle as he lights the fires and mops the floors. Dobby heard Professor McGonagall and Professor Moody in the staffroom, talking about the next task . . . Dobby cannot let Harry Potter lose his Wheezy!”

Harry’s doubts vanished. Jumping to his feet he pulled off the Invisibility Cloak, stuffed it into his bag, grabbed the gillyweed, and put it into his pocket, then tore out of the library with Dobby at his heels.