Professor Binns cleared his throat with a little snap, like a piece of chalk breaking, and went on.
"In October of that year, a special task force of Sardinian wizards—"
He faltered. Hermione's hand was waving so hard it was practically a blur.
"Miss Granger?"
"Professor, legends always have some basis in fact, don't they?"
Binns stared at her as if he'd never actually seen a student before.
"Well," he said slowly, "yes, one could put it that way."
He squinted at her like he was trying to solve a tricky equation.
"But the legend you're referring to is an extremely sensational, even laughable tale…"
Now every single person in the room was hanging on his every word.
Binns glanced around, clearly thrown by the sudden attention.
"Oh, very well," he said at last. "Let me see… The Chamber of Secrets…
"As you all know, Hogwarts was founded over a thousand years ago—the exact date is unclear—by the four greatest witches and wizards of the age. The four Houses are named after them: Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw, and Salazar Slytherin.
"They built this castle far from prying Muggle eyes, because in those days people feared magic and witches and wizards suffered much persecution."
Everyone leaned forward.
"At first the four founders were great friends, working together toward the same goal: finding young people who showed signs of magic and bringing them here to be trained.
"But slowly a rift grew. Slytherin wanted stricter standards for admission. He believed magical learning should be kept within all-magic families. He didn't want Muggle-borns—he didn't trust them.
"Eventually Slytherin and Gryffindor had a terrible row over it, and Slytherin left the school."
Binns paused again, pursing his lips like a wrinkly old tortoise.
"That," he said, "is what reliable historical record tells us."
"What about the Chamber, Professor?" Hermione pressed, sensing they were finally getting close.
"The Chamber is exactly the kind of absurd legend that grew up to obscure the facts. The story claims Slytherin built a hidden chamber in the castle that the other founders knew nothing about.
"According to the legend, Slytherin sealed the Chamber so no one could open it until his true heir arrived at the school. Only the heir could unseal the Chamber, release the horror within, and rid the school of all those deemed unworthy to study magic."
The story ended.
The classroom was dead silent, but not the usual sleepy silence of a Binns lecture.
Hermione's face had gone white. Everything clicked.
Tom Riddle had been Slytherin's heir. He'd tried to release the monster, and Sean had stopped him.
But who exactly was Tom Riddle?
"The diary, Hermione. The diary," Harry whispered, looking just as shaken.
If Sean hadn't been fighting alone every night, would the basilisk already be loose?
"There is no Chamber," Binns said firmly, gathering his notes. "No monster. The whole thing is nonsense."
…
After class, on the way to the Hope Cottage.
Ron was still shaking. "I always knew Salazar Slytherin was a twisted old nutcase, but I didn't know he started the whole pure-blood rubbish. Honestly, if the Sorting Hat had put me in Slytherin I'd have caught the next train home. No questions."
Harry was pretty sure Mrs. Weasley would have dragged him straight back by the ear, but he knew Ron didn't have a prejudiced bone in his body.
"We need to find Ginny," Hermione said, eyes sharp.
"And look—" She nodded toward Sean's usual desk in the cottage.
A massive basilisk fang sat there, calm as you please.
"He's terrifyingly strong," Ron muttered. "If Slytherin were alive today he'd take one look at Sean and change his whole philosophy. By the time Sean's his age he'll be able to take ten of him."
Ron could practically picture what had happened down in the Chamber.
"But… something's missing," he added suddenly. "Where's Sean?"
Hermione and Harry shot to their feet.
At this hour he was always in the cottage reading.
He'd never skipped breakfast either—not once.
They bolted toward the second-floor girls' bathroom and nearly crashed into Ginny.
"Ginny, what are you doing here?" Ron blurted, trying to sound casual.
Hermione's eyes zeroed in on the battered old book that looked completely out of place among Ginny's shiny new things.
"Harry, look," she breathed.
Harry followed her gaze, edged closer to Ginny, and slipped the diary out of her arms.
It practically leapt into his hands.
One glance at the cover: fifty years old, faded letters spelling T.M. Riddle.
"Right, see you!" Ron said loudly after a sharp poke from Hermione, and the three of them hurried away.
The second Ron saw the name he yelped, "I remember! Riddle won an award for special services to the school fifty years ago!"
"Later, Ron," Harry hissed.
He raised the fang, ready to stab the diary right then and there.
"Wait!" Hermione caught his wrist. "We still haven't found Sean. The diary might be useful."
They'd reached the entrance to the girls' bathroom. Peeves had been wrecking the place lately, so no one came near it anymore.
They slipped inside.
Hermione clapped a hand over her mouth the moment they crossed the threshold. Tears sprang to her eyes.
Harry and Ron looked where she was staring.
In one of the sinks sat a tiny stone statue—an alchemical toad, completely petrified.