Harry led the way to the dungeons at a run. "I just remembered," he gasped to Draco beside him. "Snape was doing research on Slytherin before he was summoned by Voldemort. It didn't seem all that significant before, but..."

"When does the man ever sleep?" Draco muttered.

They barreled right through a highly offended Bloody Baron and skidded to a halt in front of Severus' private rooms. Draco reached out a hand to test the wards. "They're very strong," he remarked. "Will we be able to take them down, do you think?"

"No need," Harry replied shortly, and touched the familiar spells with his own hand. He muttered the password under his breath, and the snake hissed a quiet greeted. The door opened silently before them. He ignored the very odd, thoughtful look Draco directly toward him.

He led them into the Potion's master's private library and stopped in front of the first of the tall goldenoak shelves. "All I see are potions books," Draco murmured from behind another shelf, his voiced tinged a little with pained amusement. "Rows and rows and rows of potions books. I don't think you can get half of these at Flourish and Blotts...or any other legitimate wizarding bookstore, for that matter."

"'Legitimate' being the operative word, of course,'" Harry commented wryly as Draco joined him. "Close your eyes."

Draco raised an eyebrow at him, but complied. Harry closed his own eyes and whispered a quiet spell, imagining the books' titles writhing apart and resolidifying into what he wanted to see. He gave the spell a moment to settle and then said, "All right."

He watched amused as a flabbergasted Draco stared at the unspelled books, eyes growing wider by the second. "Father wasn't kidding when he said that the Snapes' library was worth more than the Malfoy estate," Draco said reverently. He turned, caught sight of the tiny curve of Harry's mouth. "Well, it's a relief to know that even our acclaimed Potions master hasn't managed to accrue that many potions books," he murmured dryly.

Harry chuckled softly. "Actually, those were real books overlaid on top of more books. A rather interesting spell. And a great space-saver."

Draco closed his mouth and wrenched his cool mask back into place with effort. "Right. But fascinating as all of this is, we're still stuck for clues."

Harry scanned the shelves rapidly, searching for the heavily embossed leather spine of the book he had last seen lying by Severus' armchair. "Here!" he exclaimed finally, pulling it down from the highest shelf. He opened it, then flipped through the book until he encountered the first clear sheet of parchment covered with Severus' thin, spiky notes. He extracted it gingerly and handed it over to Draco, then turned the page and extracted the next, and the next, and the next—some twenty pages in all. "See if you can get anything from that," Harry murmured absently, and opened the book back to the first page and the passage that had caught his eye.

After a moment, he felt a nudge from Draco. "Look here," the other man said, and held up a page of Severus' notes so that the weak filtered sunlight through the dungeons windows turned it a clear frosted silver. The words flared to life like black fire. "'Slytherin left Hogwarts to seek an ancient magic, one which he believed would separate those whom he thought to be worthy of the study of magic from those who were not. He never returned from that journey. Nevertheless, there are those who speculate that he awoke that proscribed and darkest of magical arts, and even some who believe that he left its lost secrets to be found by his supposed Heir.' Sounds like Snape thought the basilisk was guarding something, too," Draco added.

"Listen—listen to this," Harry said. He cleared his throat and began to read from the book still clutched in his hands: "Corven Ocidare was the first wizard documented to have discovered the power of Blood Wizardry. His disciple, Otho Linarius, found that even the blood of Muggles held this power, and used this new form of magic to create a kingdom which he ruled from an ancient castle whose name had even then been lost to time. Otho Linarius named the castle after himself, giving it the title Toadflax Keep. Other wizards and witches followed in his footsteps, eventually creating a backlash so violent that both the wizarding and Muggle worlds went to war. After years of long, bloody battles, Otho Linarius was stripped of his armies and forced back into his castle, where he sought until he died for a way to immortality. The ramifications of the war, however, rebounded through both worlds. Muggles, terrified of the force that had so devastated their world, turned on anyone practicing magic in their midst, whether or not they used the Dark Arts. The wizarding world split along the lines of those who believed that all mention of Blood Wizardry should be erased, and those who wished to further its study. Eventually the forces of the former won over those of the latter, and wizards found practicing any sort of Blood Wizardry were immediately hunted down and executed. However, far from eliminating this art, the most powerful of the Blood Wizards went into hiding, eventually to discover the even more powerful Soul Wizardry."

"Soul Wizardry," Harry whispered. "Have you ever heard of it?"

Draco stared down at the words on the page in front of him, gaze unfocused. "Snape never spoke of it to me," he said. "The Ministry would have burned any books that they knew of. To even own something like that would probably have been enough to send you to Azkaban."

"So...Voldemort—the Heir of Slytherin—found his secrets...found..." Harry trailed off.

"Blood Wizardry. It makes sense, doesn't it?" Draco's eyes were steady and hard as granite.

"That spell he used in the graveyard..." Harry remembered. "And all those people disappearing..."

Draco said, "We need to get back to the Library."

[[center:***]]

Hermione ambushed them as soon as they got there. "We think we figured out the 'gift' and the Phoenix and Dragon," she sang out, thrusting a sheet of parchment covered in tiny little dots into Harry's hands.

"We just finished speaking with McGonagall," Ron added from the table, which was now covered with scrolls and books. His hair was damp with sweat, but he flashed them a triumphant grin.

Harry sat down slowly at the table facing Ron, squinting at the tiny white dots on the page Hermione had handed to him. They raced across the black parchment at a speed that made his eyes blur. He rubbed absently at his right temple to try to dull the throbbing that had suddenly flared into a rhythmic pain pulsing in time with the beating of his heart. "What...is this, Hermione?" he managed.

She peered over his shoulder at the parchment. "Oh! Sorry." She drew her wand and touched the tip to the whirling dots. The dots immediately stopped and began to twinkle softly.

"So that's it!" Draco exclaimed. "Dragon and Phoenix—I get it now."

"About time," Hermione said tartly. "Considering."

"I still don't," Harry interrupted with some annoyance. He abruptly dropped the parchment as a hot spear of pain stabbed into his temples from both sides. He pressed his fingertips into his brow, gasping.

"Harry?" Hermione said worriedly. "Harry, what's wrong?"

"Just a...really horrible headache," Harry managed to reply once the pain ebbed a little. "Can you...?"

"I'll go see if I can get something from Madame Pomfrey," Ron offered, and stepped into the fireplace.

"Hermione, can you explain?" Harry asked as he took his hands away and slumped into his chair, trying to relax the stiff muscles along his shoulders.

"Well, remember what you said about North Star being the 'guide in the darkness'? It kept nagging me—until I realized that the North Star wasn't supposed to be Polaris!"

Ron returned from the infirmary bearing a steaming chalice while Hermione continued her explanation. Harry murmured his thanks to Ron and took a sip, hiding his disappointment at finding that it just a bland, generic headache brew instead of Severus' cool, subtly fragrant potion.

"Although Polaris in the Little Bear is the North Star today, it isn't what the riddle meant," Hermione continued. "Because about four thousand years ago, when Merlin moved the Giants' Dance to build Stonehenge, the North Star would have been Thuban, in the constellation Draco!"

"I should have known that one," Draco admitted sheepishly.

"That fits," Harry said thoughtfully. "But what about the Phoenix? From what you're saying, that should be a constellation, too, but there's no constellation called 'Phoenix'."

"Actually, there is," Ron grinned.

Hermione nodded. "That's right. The constellation we now call 'Cygnus' was originally called 'the Phoenix.' Over the years the name was changed to the name given to it by the Muggles."

Ron jumped up and paced excitedly to the bookshelves and back. "So 'when flaming Phoenix soars with Dragon in the night' must actually be a time! That's when Snape thinks You-Know-Who is going to attack the castle!"

"That's soon, isn't it?" Harry guessed.

"Very soon," Ron agreed. He jabbed a finger at the star chart Harry held. "The constellation Draco can be seen all year 'round from where we are, but Cygnus—the Phoenix, I mean—that's going to start disappearing from the sky in the next two or three days."

"So we're running out of time," Harry murmured.

"We've been running out of time for the past year," Draco interrupted. "We just haven't known it."

Hermione gave him a sharp look. "What do you mean?"

Draco cast a glance at Harry, who nodded. Harry closed his eyes once more, deliberately trying to empty his mind of all thoughts as Draco began to fill Hermione and Ron in on what they had found. There was something important he was missing here, something he should see beneath the words. A riddle within a riddle, Severus had sent them. But...he could not rid himself of the feeling that there was more here he had not yet figured out. Something Severus had not set down in writing. Something...

"Bloody hell!" Ron exclaimed, exploding into a new round of pacing. "How does Snape expect us to fight something like this?"

"But Voldemort's not there yet," Draco pointed out. "He's just a Pawn until he can get to the promoting square."

"A damned powerful Pawn," Ron muttered.

"Professor Snape sent us this riddle for a reason," Hermione jumped in. "He must think that there's still something we can do."

"Hermione's right," Harry said firmly. "We already know the 'what' and the 'when'—that's half of the riddle."

"More than half," Hermione corrected him proudly. "We spoke to Professor McGonagall and the Aurors just before you two came back, and we think we have some idea of what the 'gift the Light bequeathed' means."

"That's actually the first part they solved—with McGonagall's help, of course," Ron added.

"So what is it?" Draco asked with a trace of impatience in his voice.

"Professor McGonagall thinks that the 'Light' Professor Snape refers to is an ancient lost race called the Lios Alfar—the Children of Light," Hermione explained. "According to legend, right before they disappeared from this world, they left behind a gift."

"Taliesin's Harp," Harry murmured.

"How'd you know that?" Ron asked, astonished.

"Albus once told me a story about them. I should have known that he doesn't do anything without a reason. And damn it, I should have thought of it before," Harry replied disgustedly.

"But how would he have—" Hermione shook her head abruptly. "Nevermind. What's important is that we have another piece of the puzzle. Tonks agreed to take us to see it. It's been locked away for almost three centuries..."

"Where?" Harry demanded.

Hermione met Harry's eyes soberly. "In the Department of Mysteries."