Barely two minutes later, the castle doors flew open yet again, and Snape came charging out of them, running toward the Willow.
Harry’s fists clenched as they watched Snape skid to a halt next to the tree, looking around. He grabbed the cloak and held it up.
“Get your filthy hands off it,” Harry snarled under his breath.
“Shh!”
Snape seized the branch Lupin had used to freeze the tree, prodded the knot, and vanished from view as he put on the cloak.
“So that’s it,” said Hermione quietly. “We’re all down there… and now we’ve just got to wait until we come back up again…”
She took the end of Buckbeak’s rope and tied it securely around the nearest tree, then sat down on the dry ground, arms around her knees.
“Harry, there’s something I don’t understand… Why didn’t the Dementors get Sirius? I remember them coming, and then I think I passed out… there were so many of them…”
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…”