“What?”

“What?”

“They can help.” He dropped his voice and said, so that none of them could hear but Hermione, who stood between them, “We don’t know where it is. We’ve got to find it fast. We don’t have to tell them it’s a Horcrux.”

Harry looked from Ron to Hermione, who murmured, “I think Ron’s right. We don’t even know what we’re looking for, we need them.” And when Harry looked unconvinced, “You don’t have to do everything alone, Harry.”

Harry thought fast, his scar still prickling, his head threatening to split again. Dumbledore had warned him against telling anyone but Ron and Hermione about the Horcruxes. Secrets and lies, that’s how we grew up, and Albus … he was a natural … Was he turning into Dumbledore, keeping his secrets clutched to his chest, afraid to trust? But Dumbledore had trusted Snape, and where had that led? To murder at the top of the highest tower …

“All right,” he said quietly to the other two. “Okay,” he called to the room at large, and all noise ceased: Fred and George, who had been cracking jokes for the benefit of those nearest, fell silent, and all of the looked alert, excited.

“There’s something we need to find,” Harry said. “Something – something that’ll help us overthrow You-Know-Who. It’s here at Hogwarts, but we don’t know where. It might have belonged to Ravenclaw. Has anyone heard of an object like that? Has anyone come across something with her eagle on it, for instance?”

He looked hopefully toward the little group of Ravenclaws, to Padma, Michael, Terry, and Cho, but it was Luna who answered, perched on the arm of Ginny’s chair.

“Well, there’s her lost diadem. I told you about it, remember, Harry? The lost diadem of Ravenclaw? Daddy’s trying to duplicate it.”

“Yeah, but the lost diadem,” said Michael Corner, rolling his eyes, “is lost, Luna. That’s sort of the point.”

“When was it lost?” asked Harry.

“Centuries ago, they say,” said Cho, and Harry’s heart sank. “Professor Flitwick says the diadem vanished with Ravenclaw herself. People have looked, but,” she appealed to her fellow Ravenclaws. “Nobody’s ever found a trace of it, have them?”

They all shook their heads.

“Sorry, but what is a diadem?” asked Ron.

“It’s a kind of crown,” said Terry Boot. “Ravenclaw’s was supposed to have magical properties, enhance the wisdom of the wearer.”

“Yes, Daddy’s Wrackspurt siphons – ”

But Harry cut across Luna.

“And none of you have ever seen anything that looks like it?”

They all shook their heads again. Harry looked at Ron and Hermione and his own disappointment was mirrored back at him. An object that had been lost this long, and apparently without trace, did not seem like a good candidate for the Horcrux hidden in the castle … Before he could formulate a new question, however, Cho spoke again.

“If you’d like to see what the diadem’s supposed to look like, I could take you up to our common room and show you, Harry. Ravenclaw’s wearing it in her statue.”

Harry’s scar scorched again: For a moment the Room of Requirement swam before him, and he saw instead the dark earth soaring beneath him and felt the great snake wrapped around his shoulders. Voldemort was flying again, whether to the underground lake or here, to the castle, he did not know: Either way, there was hardly any time left.

“He’s on the move,” he said quietly to Ron and Hermione. He glanced at Cho and then back at them. “Listen, I know it’s not much of a lead, but I’m going to go look at this statue, at least find out what the diadem looks like. Wait for me here and keep, you know – the other one – safe.”

Cho had got to her feet, but Ginny said rather fiercely, “No, Luna will take Harry, won’t you, Luna?”

“Oooh, yes, I’d like to,” said Luna happily, as Cho sat down again, looking disappointed.

“How do we get out?” Harry asked Neville.

“Over here.”

He led Harry and Luna to a corner, where a small cupboard opened onto a steep staircase. “It comes out somewhere different every day, so they’ve never been able to find it,” he said. “Only trouble is, we never know exactly where we’re going to end up when we go out. Be careful, Harry, they’re always patrolling the corridors at night.”

“No problem,” said Harry. “See you in a bit.”

He and Luna hurried up the staircase, which was long, lit by torches, and turned corners in unexpected places. At last they reached what appeared to be solid wall.

“Get under here,” Harry told Luna, pulling out the Invisibility Cloak and throwing it over both of them. He gave the wall a little push.

It melted away at his touch and they slipped outside. Harry glanced back and saw that it had resealed itself at once. They were standing in a dark corridor. Harry pulled Luna back into the shadows, fumbled in the pouch around his neck, and took out the Marauder’s Map. Holding it close to his nose he searched, and located his and Luna’s dots at last.

“We’re up on the fifth floor,” he whispered, watching filch moving away from them, a corridor ahead. “Come on, this way.”

They crept off.

Harry had prowled the castle at night many times before, but never had his heart hammered that fast, never had so much depended on his safe passage through the place. Through squares of moonlight upon the floor, past suits of armor whose helmets creaked at the sound of their soft footsteps, around corners beyond which who knew what lurked. Harry and Luna walked, checking the Marauder’s Map whenever light permitted, twice pausing to allow a ghost to pass without drawing attention to themselves. He expected to encounter an obstacle at any moment; his worst fear was Peeves, and he strained his ears with every step to hear the first, telltale signs of the poltergeist’s approach.

“The way, Harry,” breathed Luna, plucking his sleeve and pulling him toward a spiral staircase.

They climbed in tight, dizzying circles; Harry had never been up here before. At last they reached a door. There was no handle and no keyhole: nothing but a plain expanse of aged wood, and a bronze knocker in the shape an eagle.

Luna reached out a pale hand, which looked eerie floating in midair, unconnected to arm or body. She knocked once, and in the silence it sounded to Harry like a cannon blast. At once the beak of the eagle opened, but instead of a bird’s called, a soft, musical voice said, “Which came first, the phoenix or the flame?”

“Hmm … What do you think, Harry?” said Luna, looking thoughtful.

“What? Isn’t there a password?”

“Oh no, you’ve got to answer a question,” said Luna.

“What if you get it wrong?”

“Well, you have to wait for somebody who gets it right,” said Luna. “That way you learn, you see?”

“Yeah … Trouble is, we can’t really afford to wait for anyone else, Luna.”

“No, I see what you mean,” said Luna seriously. “Well then, I think the answer is that a circle has no beginning.”

“Well reasoned,” said the voice, and the door swung open.

The deserted Ravenclaw common room was a wide, circular room, airier than any Harry had ever seen at Hogwarts. Graceful arched windows punctuated the walls, which were hung with blue-and-bronze silks. By day, the Ravenclaws would have a spectacular view of the surrounding mountains. The ceiling was domed and painted with stars, which were echoed in the midnight-blue carpet. There were tables, chairs, and bookcases, and in a niche opposite the door stood a tall statue of white marble.