Ducking under Peeves, they ran for their lives, right to the end of the corridor where they slammed into a door -- and it was locked.

　　"This is it!" Ron moaned, as they pushed helplessly at the door, "We're done for! This is the end!" They could hear footsteps, Filch running as fast as he could toward Peeves's shouts.

　　"Oh, move over," Hermione snarled. She grabbed Harry's wand, tapped the lock, and whispered, 'Alohomora!"

　　The lock clicked and the door swung open -- they piled through it, shut it quickly, and pressed their ears against it, listening.

　　"Which way did they go, Peeves?" Filch was saying. "Quick, tell me."

　　"Say 'please."'

　　"Don't mess with me, Peeves, now where did they go?"

　　"Shan't say nothing if you don't say please," said Peeves in his annoying singsong voice.

　　"All right -please."

　　"NOTHING! Ha haaa! Told you I wouldn't say nothing if you didn't say please! Ha ha! Haaaaaa!" And they heard the sound of Peeves whooshing away and Filch cursing in rage.

　　"He thinks this door is locked," Harry whispered. "I think we'll be okay -- get off, Neville!" For Neville had been tugging on the sleeve of Harry's bathrobe for the last minute. "What?"

　　Harry turned around -- and saw, quite clearly, what. For a moment, he was sure he'd walked into a nightmare -- this was too much, on top of everything that had happened
so far.

　　They weren't in a room, as he had supposed. They were in a corridor. The forbidden corridor on the third floor. And now they knew why it was forbidden.

　　They were looking straight into the eyes of a monstrous dog, a dog that filled the whole space between ceiling and floor. It had three heads. Three pairs of rolling, mad eyes; three noses, twitching and quivering in their direction; three drooling mouths, saliva hanging in slippery ropes from yellowish fangs.
　　
It was standing quite still, all six eyes staring at them, and Harry knew that the only reason they weren't already dead was that their sudden appearance had taken it by surprise, but it was quickly getting over that, there was no mistaking what those thunderous growls meant.

　　Harry groped for the doorknob -- between Filch and death, he'd take Filch.

　　They fell backward -- Harry slammed the door shut, and they ran, they almost flew, back down the corridor. Filch must have hurried off to look for them somewhere else, because they didn't see him anywhere, but they hardly cared -- all they wanted to do was put as much space as possible between them and that monster. They didn't stop running until they reached the portrait of the Fat Lady on the seventh floor.

　　"Where on earth have you all been?" she asked, looking at their bathrobes hanging off their shoulders and their flushed, sweaty faces.

　　"Never mind that -- pig snout, pig snout," panted Harry, and the portrait swung forward. They scrambled into the common room and collapsed, trembling, into armchairs.

　　It was a while before any of them said anything. Neville, indeed, looked as if he'd never speak again.

　　"What do they think they're doing, keeping a thing like that locked up in a school?" said Ron finally. "If any dog needs exercise, that one does."

　　Hermione had got both her breath and her bad temper back again. "You don't use your eyes, any of you, do you?" she snapped. "Didn't you see what it was standing on.

　　"The floor?" Harry suggested. "I wasn't looking at its feet, I was too busy with its heads."

　　"No, not the floor. It was standing on a trapdoor. It's obviously guarding something."

　　She stood up, glaring at them.

　　I hope you're pleased with yourselves. We could all have been killed -- or worse, expelled. Now, if you don't mind, I'm going to bed."

　　Ron stared after her, his mouth open.

　　"No, we don't mind," he said. "You'd think we dragged her along, wouldn't you.

　　But Hermione had given Harry something else to think about as he climbed back into bed. The dog was guarding something.... What had Hagrid said? Gringotts was the
safest place in the world for something you wanted to hide -- except perhaps Hogwarts.

It looked as though Harry had found out where the grubby littie package from vault seven hundred and thirteen was.