Harry found Ron at the back of the library, measuring his History of Magic homework. Professor Binns had asked for a three foot long composition on “The Medieval Assembly of European Wizards.”

“I don’t believe it, I’m still eight inches short said Ron furiously, letting go of his parchment, which sprang back into a roll. “And Hermione’s done four feet seven inches and her writing’s tiny.”

“Where is she?” asked Harry, grabbing the tape measure and unrolling his own homework.

“Somewhere over there,” said Ron, pointing along the shelves. “Looking for another book. I think she’s trying to read the whole library before Christmas.”

Harry told Ron about Justin Finch-Fletchley running away from him.

“Dunno why you care. I thought he was a bit of an idiot,” said Ron, scribbling away, making his writing as large as possible. “All that junk about Lockhart being so great —”

Hermione emerged from between the bookshelves. She looked irritable and at last seemed ready to talk to them.

“All the copies of Hogwarts, A History have been taken out,” she said, sitting down next to Harry and Ron. “And there’s a two-week waiting list. I wish I hadn’t left my copy at home, but I couldn’t fit it in my trunk with all the Lockhart books.”

“Why do you want it?” said Harry.

“The same reason everyone else wants it,” said Hermione, “to read up on the legend of the Chamber of Secrets.”

“What’s that?” said Harry quickly.

“That’s just it. I can’t remember,” said Hermione, biting her lip. “And I can’t find the story anywhere else —”

“Hermione, let me read your composition,” said Ron desperately, checking his watch.

“No, I won’t,” said Hermione, suddenly severe. “You’ve had ten days to finish it —”

“I only need another two inches, come on —”

The bell rang. Ron and Hermione led the way to History of Magic, bickering.

History of Magic was the dullest subject on their schedule. Professor Binns, who taught it, was their only ghost teacher, and the most exciting thing that ever happened in his classes was his entering the room through the blackboard. Ancient and shriveled, many people said he hadn’t noticed he was dead. He had simply got up to teach one day and left his body behind him in an armchair in front of the staff room fire; his routine had not varied in the slightest since.

Today was as boring as ever. Professor Binns opened his notes and began to read in a flat drone like an old vacuum cleaner until nearly everyone in the class was in a deep stupor, occasionally coming to long enough to copy down a name or date, then falling asleep again. He had been speaking for half an hour when something happened that had never happened before. Hermione put up her hand.

Professor Binns, glancing up in the middle of a deadly dull lecture on the International Warlock Convention of 1289, looked amazed.

“Miss — er —?”

“Granger, Professor. I was wondering if you could tell us anything about the Chamber of Secrets,” said Hermione in a clear voice.

Dean Thomas, who had been sitting with his mouth hanging open, gazing out of the window, jerked out of his trance; Lavender Brown’s head came up off her arms and Neville Longbottom’s elbow slipped off his desk.

Professor Binns blinked.

“My subject is History of Magic,” he said in his dry, wheezy voice. “I deal with facts , Miss Granger, not myths and legends.” He cleared his throat with a small noise like chalk slipping and continued, “In September of that year, a subcommittee of Sardinian sorcerers —”

He stuttered to a halt. Hermione’s hand was waving in the air again.

“Miss Grant?”

“Please, sir, don’t legends always have a basis in fact?”

Professor Binns was looking at her in such amazement, Harry was sure no student had ever interrupted him before, alive or dead.

“Well,” said Professor Binns slowly, “yes, one could argue that, I suppose.” He peered at Hermione as though he had never seen a student properly before. “However, the legend of which you speak is such a very sensational , even ludicrous tale —”

But the whole class was now hanging on Professor Binns’s every word. He looked dimly at them all, every face turned to his. Harry could tell he was completely thrown by such an unusual show of interest.

“Oh, very well,” he said slowly. “Let me see…the Chamber of Secrets…

“You all know, of course, that Hogwarts was founded over a thousand years ago — the precise date is uncertain — by the four greatest witches and wizards of the age. The four school Houses are named after them: Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw, and Salazar Slytherin. They built this castle together, far from prying Muggle eyes, for it was an age when magic was feared by common people, and witches and wizards suffered much persecution.”

He paused, gazed blearily around the room, and continued.

“For a few years, the founders worked in harmony together, seeking out youngsters who showed signs of magic and bringing them to the castle to be educated. But then disagreements sprang up between them. A rift began to grow between Slytherin and the others. Slytherin wished to be more selective about the students admitted to Hogwarts. He believed that magical learning should be kept within all-magic families. He disliked taking students of Muggle parentage, believing them to be untrustworthy. After a while, there was a serious argument on the subject between Slytherin and Gryffindor, and Slytherin left the school.”

Professor Binns paused again, pursing his lips, looking like a wrinkled old tortoise.

“Reliable historical sources tell us this much,” he said. “But these honest facts have been obscured by the fanciful legend of the Chamber of Secrets. The story goes that Slytherin had built a hidden chamber in the castle, of which the other founders knew nothing.

“Slytherin, according to the legend, sealed the Chamber of Secrets so that none would be able to open it until his own true heir arrived at the school. The heir alone would be able to unseal the Chamber of Secrets, unleash the horror within, and use it to purge the school of all who were unworthy to study magic.”

There was silence as he finished telling the story, but it wasn’t the usual, sleepy silence that filled Professor Binns’s classes. There was unease in the air as everyone continued to watch him, hoping for more. Professor Binns looked faintly annoyed.

“The whole thing is arrant nonsense, of course,” he said. “Naturally, the school has been searched for evidence of such a chamber, many times, by the most learned witches and wizards. It does not exist. A tale told to frighten the gullible.”

Hermione’s hand was back in the air.

“Sir — what exactly do you mean by the ‘horror within’ the Chamber?”

“That is believed to be some sort of monster, which the Heir of Slytherin alone can control,” said Professor Binns in his dry, reedy voice.

The class exchanged nervous looks.

“I tell you, the thing does not exist,” said Professor Binns, shuffling his notes. “There is no Chamber and no monster.”

“But, sir,” said Seamus Finnigan, “if the Chamber can only be opened by Slytherin’s true heir, no one else would be able to find it, would they?”

“Nonsense, O’Flaherty,” said Professor Binns in an aggravated tone. “If a long succession of Hogwarts headmasters and headmistresses haven’t found the thing —”

“But, Professor,” piped up Parvati Patil, “you’d probably have to use Dark Magic to open it —”

“Just because a wizard doesn’t use Dark Magic doesn’t mean he can’t , Miss Pennyfeather,” snapped Professor Binns. “I repeat, if the likes of Dumbledore —”

“But maybe you’ve got to be related to Slytherin, so Dumbledore couldn’t —” began Dean Thomas, but Professor Binns had had enough.

“That will do,” he said sharply. “It is a myth! It does not exist! There is not a shred of evidence that Slytherin ever built so much as a secret broom cupboard! I regret telling you such a foolish story! We will return, if you please, to history , to solid, believable, verifiable fact !”

And within five minutes, the class had sunk back into its usual torpor.

“I always knew Salazar Slytherin was a twisted old loony,” Ron told Harry and Hermione as they fought their way through the teeming corridors at the end of the lesson to drop off their bags before dinner. “But I never knew he started all this pure-blood stuff. I wouldn’t be in his house if you paid me. Honestly, if the Sorting Hat had tried to put me in Slytherin, I’d’ve got the train straight back home…”

Hermione nodded fervently, but Harry didn’t say anything. His stomach had just dropped unpleasantly.

Harry had never told Ron and Hermione that the Sorting Hat had seriously considered putting him in Slytherin. He could remember, as though it were yesterday, the small voice that had spoken in his ear when he’d placed the hat on his head a year before: You could be great, you know, it’s all here in your head, and Slytherin would help you on the way to greatness, no doubt about that …

But Harry, who had already heard of Slytherin House’s reputation for turning out Dark wizards, had thought desperately, Not Slytherin! and the hat had said, Oh, well, if you’re sure …better be Gryffindor .…

As they were shunted along in the throng, Colin Creevy went past.

“Hiya, Harry!”

“Hullo, Colin,” said Harry automatically.

“Harry — Harry — a boy in my class has been saying you’re —”

But Colin was so small he couldn’t fight against the tide of people bearing him toward the Great Hall; they heard him squeak, “See you, Harry!” and he was gone.

“What’s a boy in his class saying about you?” Hermione wondered.

“That I’m Slytherin’s heir, I expect,” said Harry, his stomach dropping another inch or so as he suddenly remembered the way Justin Finch-Fletchley had run away from him at lunchtime.

“People here’ll believe anything,” said Ron in disgust.

The crowd thinned and they were able to climb the next staircase without difficulty.

“D’you really think there’s a Chamber of Secrets?” Ron asked Hermione.

“I don’t know,” she said, frowning. “Dumbledore couldn’t cure Mrs. Norris, and that makes me think that whatever attacked her might not be — well — human.”