J. Rowling - Harry Potter and the Prisoner of Azkaban

“Harry,” Hermione muttered as though she knew exactly what he was thinking, “we’ve got to stay put. We mustn’t be seen. There’s nothing we can do…”

“So we’re just going to let Pettigrew escape all over again…” said Harry quietly.

“How do you expect to find a rat in the dark?” snapped Hermione. “There’s nothing we can do! We came back to help Sirius; we’re not supposed to be doing anything else!”

“All right!”

The moon slid out from behind its cloud. They saw the tiny figures across the grounds stop. Then they saw movement—

“There goes Lupin,” Hermione whispered. “He’s transforming—”

“Hermione!” said Harry suddenly. “We’ve got to move!”

“We mustn’t, I keep telling you—”

“Not to interfere! Lupin’s going to run into the forest, right at us!”

Hermione gasped.

“Quick!” she moaned, dashing to untie Buckbeak. “Quick! Where are we going to go? Where are we going to hide? The Dementors wilt be coming any moment—”

“Back to Hagrid’s!” Harry said. “It’s empty now—come on!”

They ran as fast as they could, Buckbeak cantering along behind them. They could hear the werewolf howling behind them…

The cabin was in sight; Harry skidded to the door, wrenched it open, and Hermione and Buckbeak flashed past him; Harry threw himself in after them and bolted the door. Fang the boarhound barked loudly.

“Shh, Fang, it’s us!” said Hermione, hurrying over and scratching his ears to quieten him. “That was really close!” she said to Harry.

“Yeah…”

Harry was looking out of the window. It was much harder to see what was going on from here. Buckbeak seemed very happy to find himself back inside Hagrid’s house. He lay down in front of the fire, folded his wings contentedly, and seemed ready for a good nap.

“I think I’d better go outside again, you know,” said Harry slowly. “I can’t see what’s going on—we won’t know when it’s time—”

Hermione looked up. Her expression was suspicious.

“I’m not going to try and interfere,” said Harry quickly. “But if we don’t see what’s going on, how’re we going to know when it’s time to rescue Sirius?”

“Well… okay, then… I’ll wait here with Buckbeak… but Harry, be careful—there’s a werewolf out there—and the Dementors—”

Harry stepped outside again and edged around the cabin. He could hear yelping in the distance. That meant the Dementors were closing in on Sirius… He and Hermione would be running to him any moment…

Harry stared out toward the lake, his heart doing a kind of drumroll in his chest… Whoever had sent that Patronus would be appearing at any moment…

For a fraction of a second he stood, irresolute, in front of Hagrid’s door. You must not be seen. But he didn’t want to be seen. He wanted to do the seeing… He had to know…

And there were the Dementors. They were emerging out of the darkness from every direction, gliding around the edges of the lake… They were moving away from where Harry stood, to the opposite bank… He wouldn’t have to get near them…

Harry began to run. He had no thought in his head except his father… If it was him… if it really was him… he had to know, had to find out…

The lake was coming nearer and nearer, but there was no sign of anybody. On the opposite bank, he could see tiny glimmers of silver—his own attempts at a Patronus—

There was a bush at the very edge of the water. Harry threw himself behind it, peering desperately through the leaves. On the opposite bank, the glimmers of silver were suddenly extinguished. A terrified excitement shot through him—any moment now—

“Come on!” he muttered, staring about. “Where are you? Dad, come on—”

But no one came. Harry raised his head to look at the circle of Dementors across the lake. One of them was lowering its hood. It was time for the rescuer to appear—but no one was coming to help this time—

And then it hit him—he understood. He hadn’t seen his father—he had seen himself—

Harry flung himself out from behind the bush and pulled out his wand.

“EXPECTO PATRONUM!” he yelled.

And out of the end of his wand burst, not a shapeless cloud of mist, but a blinding, dazzling, silver animal. He screwed up his eyes, trying to see what it was. It looked like a horse. It was galloping silently away from him, across the black surface of the lake. He saw it lower its head and charge at the swarming Dementors… Now it was galloping around and around the black shapes on the ground, and the Dementors were falling back, scattering, retreating into the darkness… They were gone.

The Patronus turned. It was cantering back toward Harry across the still surface of the water. It wasn’t a horse. It wasn’t a unicorn, either. It was a stag. It was shining brightly as the moon above… it was coming back to him…

It stopped on the bank. Its hooves made no mark on the soft ground as it stared at Harry with its large, silver eyes. Slowly, it bowed its antlered head. And Harry realized…

“Prongs,” he whispered.

But as his trembling fingertips stretched toward the creature, it vanished.

Harry stood there, hand still outstretched. Then, with a great leap of his heart, he heard hooves behind him—he whirled around and saw Hermione dashing toward him, dragging Buckbeak behind her.

“What did you do?” she said fiercely. “You said you were only going to keep a lookout!”

“I just saved all our lives…” said Harry. “Get behind here—behind this bush—I’ll explain.”

Hermione listened to what had just happened with her mouth open yet again.

“Did anyone see you?”

“Yes, haven’t you been listening? I saw me but I thought I was my dad! It’s okay!”

“Harry, I can’t believe it… You conjured up a Patronus that drove away all those Dementors! That’s very, very advanced magic.”

“I knew I could do it this time,” said Harry, “because I’d already done it… Does that make sense?”

“I don’t know—Harry, look at Snape!”

Together they peered around the bush at the other bank. Snape had regained consciousness. He was conjuring stretchers and lifting the limp forms of Harry, Hermione, and Black onto them. A fourth stretcher, no doubt bearing Ron, was already floating at his side. Then, wand held out in front of him, he moved them away toward the castle.

“Right, it’s nearly time,” said Hermione tensely, looking at her watch. “We’ve got about forty five minutes until Dumbledore locks the door to the hospital wing. We’ve got to rescue Sirius and get back into the ward before anybody realizes we’re missing…”

They waited, watching the moving clouds reflected in the lake, while the bush next to them whispered in the breeze. Buckbeak, bored, was ferreting for worms again.

“D’ you reckon he’s up there yet?” said Harry, checking his watch. He looked up at the castle and began counting the windows to the right of the West Tower.

“Look!” Hermione whispered. “Who’s that? Someone’s coming back out of the castle!”

Harry stared through the darkness. The man was hurrying across the grounds, toward one of the entrances. Something shiny glinted in his belt.

“Macnair!” said Harry. “The executioner! He’s gone to get the Dementors! This is it, Hermione—”

Hermione put her hands on Buckbeak’s back and Harry gave her a leg up. Then he placed his foot on one of the lower branches of the bush and climbed up in front of her. He pulled Buckbeak’s rope back over his neck and tied it to the other side of his collar like reins.

“Ready?” he whispered to Hermione. “You’d better hold on to me—”