Harry sat down too. He explained what he’d seen; how, as the nearest dementor had lowered its mouth to Harry’s, a large silver something had come galloping across the lake and forced the dementors to retreat.

Hermione’s mouth was slightly open by the time Harry had finished.

“But what was it?”

“There’s only one thing it could have been, to make the dementors go,” said Harry. “A real Patronus. A powerful one.”

“But who conjured it?”

Harry didn’t say anything. He was thinking back to the person he’d seen on the other bank of the lake. He knew who he thought it had been . . . but how could it have been?

“Didn’t you see what they looked like?” said Hermione eagerly. “Was it one of the teachers?”

“No,” said Harry. “He wasn’t a teacher.”

“But it must have been a really powerful wizard, to drive all those dementors away . . . If the Patronus was shining so brightly, didn’t it light him up? Couldn’t you see—?”

“Yeah, I saw him,” said Harry slowly. “But . . . maybe I imagined it . . . I wasn’t thinking straight . . . I passed out right afterward . . . ”

“Who did you think it was?”

“I think—” Harry swallowed, knowing how strange this was going to sound. “I think it was my dad.”

Harry glanced up at Hermione and saw that her mouth was fully open now. She was gazing at him with a mixture of alarm and pity.

“Harry, your dad’s—well—dead,” she said quietly.

“I know that,” said Harry quickly.

“You think you saw his ghost?”

“I don’t know . . . no . . . he looked solid . . . ”

“But then—”

“Maybe I was seeing things,” said Harry. “But . . . from what I could see . . . it looked like him . . . I’ve got photos of him . . . ”

Hermione was still looking at him as though worried about his sanity.

“I know it sounds crazy,” said Harry flatly. He turned to look at Buckbeak, who was digging his beak into the ground, apparently searching for worms. But he wasn’t really watching Buckbeak.

He was thinking about his father and about his father’s three oldest friends . . . Moony, Wormtail, Padfoot, and Prongs . . . Had all four of them been out on the grounds tonight? Wormtail had reappeared this evening when everyone had thought he was dead . . . Was it so impossible his father had done the same? Had he been seeing things across the lake? The figure had been too far away to see distinctly . . . yet he had felt sure, for a moment, before he’d lost consciousness . . .

The leaves overhead rustled faintly in the breeze. The moon drifted in and out of sight behind the shifting clouds. Hermione sat with her face turned toward the Willow, waiting.

And then, at last, after over an hour . . .

“Here we come!” Hermione whispered.