“Ravenclaws, follow on!” cried Professor McGonagall.

Slowly the four tables emptied. The Slytherin table was completely deserted, but a number of older Ravenclaws remained seated while their fellows filed out; even more Hufflepuffs stayed behind, and half of Gryffindor remained in their seats, necessitating Professor McGonagall’s descent from the teachers’ platform to chivvy the underage on their way.

“Absolutely not, Creevey, go! And you, Peakes!”

Harry hurried over to the Weasleys, all sitting together at the Gryffindor table.

“Where are Ron and Hermione?”

“Haven’t you found—?” began Mr. Weasley, looking worried.

But he broke off as Kingsley had stepped forward on the raised platform to address those who had remained behind.

“We’ve only got half an hour until midnight, so we need to act fast. A battle plan has been agreed between the teachers of Hogwarts and the Order of the Phoenix. Professors Flitwick, Sprout and McGonagall are going to take groups of fighters up to the three highest towers—Ravenclaw, Astronomy, and Gryffindor—where they’ll have good overview, excellent positions from which to work spells. Meanwhile Remus”—he indicated Lupin—“Arthur”—he pointed toward Mr. Weasley, sitting at the Gryffindor table—“and I will take groups into the grounds. We’ll need somebody to organize defense of the entrances or the passageways into the school—”

“Sounds like a job for us,” called Fred, indicating himself and George, and Kingsley nodded his approval.

“All right, leaders up here and we’ll divide up the troops!”

“Potter,” said Professor McGonagall, hurrying up to him, as students flooded the platform, jostling for position, receiving instructions, “Aren’t you supposed to be looking for something?”

“What? Oh,” said Harry, “oh yeah!”

He had almost forgotten about the Horcrux, almost forgotten that the battle was being fought so that he could search for it: The inexplicable absence of Ron and Hermione had momentarily driven every other thought from his mind.

“Then go, Potter, go!”

“Right—yeah—”

He sensed eyes following him as he ran out of the Great Hall again, into the entrance hall still crowded with evacuating students. He allowed himself to be swept up the marble staircase with them, but at the top he hurried off along a deserted corridor. Fear and panic were clouding his thought processes. He tried to calm himself, to concentrate on finding the Horcrux, but his thoughts buzzed as frantically and fruitlessly as wasps trapped beneath a glass. Without Ron and Hermione to help him he could not seem to marshal his ideas. He slowed down, coming to a halt halfway along a passage, where he sat down on the plinth of a departed statue and pulled the Marauder’s Map out of the pouch around his neck. He could not see Ron’s or Hermione’s names anywhere on it, though the density of the crowd of dots now making its way to the Room of Requirement might, he thought, be concealing them. He put the map away, pressed his hands over his face, and closed his eyes, trying to concentrate.

Voldemort thought I’d go to Ravenclaw Tower.

There it was, a solid fact, the place to start. Voldemort had stationed Alecto Carrow in the Ravenclaw common room, and there could be only one explanation; Voldemort feared that Harry already knew his Horcrux was connected to that House.

But the only object anyone seemed to associate with Ravenclaw was the lost diadem… and how could the Horcrux be the diadem? How was it possible that Voldemort, the Slytherin, had found the diadem that had eluded generations of Ravenclaws? Who could have told him where to look, when nobody had seen the diadem in living memory?

In living memory…

Beneath his fingers, Harry’s eyes flew open again. He leapt up from the plinth and tore back the way he had come, now in pursuit of his one last hope. The sound of hundreds of people marching toward the Room of Requirement grew louder and louder as he returned to the marble stairs. Prefects were shouting instructions, trying to keep track of the students in their own houses, there was much pushing and shouting; Harry saw Zacharias Smith bowling over first years to get to the front of the queue, here and there younger students were in tears, while older ones called desperately for friends or siblings.

Harry caught sight of a pearly white figure drifting across the entrance hall below and yelled as loudly as he could over the clamor.

“Nick! NICK! I need to talk to you!”

He forced his way back through the tide of students, finally reaching the bottom of the stairs, where Nearly Headless Nick, ghost of Gryffindor Tower, stood waiting for him.

“Harry! My dear boy!”

Nick made to grasp Harry’s hands with both of his own; Harry felt as though they had been thrust into icy water.

“Nick, you’ve got to help me. Who’s the ghost of Ravenclaw Tower?”

Nearly Headless Nick looked surprised and a little offended.

“The Gray Lady, of course; but if it is ghostly services you require—?”

“It’s got to be her—d’you know where she is?”

“Let’s see…”

Nick’s head wobbled a little on his ruff as he turned hither and thither, peering over the heads of the swarming students.

“That’s her over there, Harry, the young woman with the long hair.”

Harry looked in the direction of Nick’s transparent, pointing finger and saw a tall ghost who caught sight of Harry looking at her, raised her eyebrows, and drifted away through a solid wall.

Harry ran after her. Once through the door of the corridor into which she had disappeared, he saw her at the very end of the passage, still gliding smoothly away from him.

“Hey—wait—come back!”

She consented to pause, floating a few inches from the ground. Harry supposed that she was beautiful, with her waist-length hair and floor-length cloak, but she also looked haughty and proud. Close in, he recognized her as a ghost he had passed several times in the corridor, but to whom he had never spoken.

“You’re the Gray Lady?”

She nodded but did not speak.

“The ghost of Ravenclaw Tower?”

“That is correct.”

Her tone was not encouraging.

“Please, I need some help. I need to know anything you can tell me about the lost diadem.”

A cold smile curved her lips.

“I am afraid,” she said, turning to leave, “that I cannot help you.”

“WAIT!”

He had not meant to shout, but anger and panic were threatening to overwhelm him. He glanced at his watch as she hovered in front of him. It was a quarter to midnight.

“This is urgent,” he said fiercely. “If that diadem’s at Hogwarts, I’ve got to find it, fast.”

“You are hardly the first student to covet the diadem,” she said disdainfully. “Generations of students have badgered me—”

“This isn’t about trying to get better marks!” Harry shouted at her, “It’s about Voldemort—defeating Voldemort—or aren’t you interested in that?”

She could not blush, but her transparent cheeks became more opaque, and her voice was heated as she replied, “Of course I—how dare you suggest—?”

“Well, help me then!”

Her composure was slipping.

“It—it is not a question of—” she stammered. “My mother’s diadem—”

“Your mother’s?”

She looked angry with herself.

“When I lived,” she said stiffly, “I was Helena Ravenclaw.”

“You’re her daughter? But then, you must know what happed to it.”

“While the diadem bestows wisdom,” she said with an obvious effort to pull herself together, “I doubt that it would greatly increase you chances of defeating the wizard who calls himself Lord—”

“Haven’t I told you, I’m not interested in wearing it!” Harry said fiercely. “There’s no time to explain—but if you care about Hogwarts, if you want to see Voldemort finished, you’ve got to tell me anything you know about the diadem!”

She remained quite still, floating in midair, staring down at him, and a sense of hopelessness engulfed Harry. Of course, if she had known anything, she would have told Flitwick of Dumbledore, who had surely asked her the same question. He had shaken his head and made to turn away when she spoke in a low voice.