"It's a riddle," Hermione murmured softly a little while later, fingers tracing the black lines etched onto the parchment in her hands as if she were memorizing it by touch alone. "If I just knew the structure... If I could find somewhere to begin...."

"Hermione, stop a minute," Ron commanded, snatching the parchment from her and giving her a look of such seriousness that it stopped her protest mid-syllable. "Harry, sit down."

Harry obeyed reluctantly, stamping hard on the urge to pace until exhaustion drove the dread from his mind. Tonks, Shacklebolt, and the other Aurors were holding their own counsel in McGonagall's office. But Hermione's agitated footsteps had brought them to the Hogwarts Library, her home ground, and it was here they'd chosen as their starting point for hammering out Severus' puzzle.

"What's this all about, Weasley? Surely Ms. Granger, the genius inventor of ciphrascriptology, will find little challenge in a mere riddle," Draco drawled from his perch on a nearby stool.

Ron glared up at the Slytherin. "What are you doing here, Malfoy? Don't you have better things to do than tag along with three Gryffindors?"

"Grow up, Weasley," Draco responded disdainfully. "You really don't think I'd stick around with those fools from the Ministry, do you? Malfoys only deal with the best, and at the moment, that appears to be you three. Tragically."

Ron snorted and turned his back on Draco. "Harry, mate, now's the time to come clean. We know that something happened that Christmas. We don't know what, and we won't ask. But just tell us—do you still trust Snape? Is he leading us into a trap?"

Harry looked down at his hands, lying twisted around each other in his lap. "Ron..."

"Just tell me," his friend said earnestly. "You know that I don't trust Snape further than I can throw him without magic, but you I'll follow over a cliff and into the pits of hell if you need me."

Harry looked up and swallowed hard at the sincerity in Ron's eyes, his throat tightening. And suddenly, in that moment, he finally recalled the words of Albus' Will. "Yes, Ron," he replied hoarsely, holding his friend's gaze, "I do trust him. With my life."

There was something that he had not said. He knew that Ron had realized it, but he only nodded. "Does that mean we can get back on track now?" Draco impatient voice interrupted them. Harry glanced at him, a little surprised that he had remained silent during that exchange. But Draco only gazed back at him with narrow-eyed thoughtfulness.

Harry turned to Hermione. "You solved Snape's puzzle at the end of our First Year, Hermione, do you remember? You can figure this one out, too," he said quietly.

"Well, I can't solve this one alone, so I'm going to need all of your help," Hermione replied firmly. "Malfoy, get out unless you're planning to make yourself useful." She raised an eyebrow at him, and he bowed slightly.

"At your command, milady."

She rolled her eyes. "Then tell me if there's anything that strikes you about this riddle."

They all took copies of the riddle from Hermione. After a few long minutes of silence, Harry asked tentatively, "Hermione, what did you mean by 'anything that strikes you'? Just what are we looking for?" He traced a line with his fingertips.

"Look at it. The riddle doesn't have enough clues to be solved on its own, so Professor Snape obviously thinks that we should be able to fill in the blanks," Hermione explained briskly.

"We might, if it didn't have so many blanks," Ron grumbled.

"Just think about it," Harry told his friend softly, shooting a glance at Draco to forestall the snide comment he knew was coming. Draco only raised an ironic eyebrow at him.

Predictably, it was Hermione who next broke the silence. "There are bits and pieces in here that make sense. They're like little landmarks telling us where to go. But I just can't see the entire map right now. All I can think is...what Harry said about the puzzle during our first year..." All of a sudden she jumped up. "It's a long shot, but I have an idea. I'll be right back." And she ran into the fireplace.

Harry, Ron, and Draco looked at each other. "Landmarks? All I see are snakes and phoenixes and dragons and old Merlin not acting in his right mind," Ron groused.

Hermione was back through the fireplace a minute later, floating a large stone rune-engraved basin in front of her that Harry recognized at once. "I borrowed it from the Headmaster," Hermione explained shortly, and sat it carefully down on the table. Then she quickly drew her wand and touched it to her temple. A single silvery strand of memory trailed from her wand and fell curling into the Pensieve. "That is the strangest feeling," she said with an odd expression on her face, before diving right inside.

Harry, Ron, and Draco gave each other identical bewildered looks. Then as one they reached for Hermione.

Harry swirled through a familiar darkness, swallowing thickly against the nauseating sense of vertigo. He opened his eyes when his feet touched the ground with a jolt, to see that they were standing in a stone chamber, facing a table with a row of seven bottles, all of them differently shaped. "Is that...?" Harry murmured. Ron jumped as violet flames sprang up behind them, sealing the exit. Black flames blocked the front.

"Blimey, what is this place?" Ron asked.

A girl and a boy with messy hair approached the table. "The chamber beyond the chess set—Snape's challenge from First Year," Harry answered his friend absently. Hermione had walked over to her childhood self, watching intently as her memory scene played out in front of her.

"Look!" the younger Hermione exclaimed, picking up a scroll lying beside the row of bottles. The younger Harry moved to peer over her shoulder, and Draco, Ron, and Harry followed.

Hermione was standing behind her memory self. After a moment, she began reading the puzzle out loud: Danger lies before you, while safety lies behind / Two of us will help you, whichever you would find / One among us seven will let you move ahead / Another will transport the drinker back instead / Two among our number hold only nettle-wine / Three of us are killers, waiting hidden in line / Choose, unless you wish to stay here forevermore / To help you in your choice, we give you these clues four: / First, however slyly the poison tries to hide / You will always find some on nettle wine's left side / Second, different are those who stand at either end / But if you would move onward, neither is your friend; / Third as you see clearly, all are different size / Neither dwarf nor giant hold death in their insides; / Fourth, the second left and the second on the right / Are twins once you taste them, though different at first sight.

And then Hermione was turning towards them with the same brilliant smile that her younger self was giving the eleven-year-old Harry. "Come on!" she said. She stepped through the violet flames at the rear of the room. Harry cast one look back as their memory selves took their potions, then followed Hermione. He found himself back in the library, with Draco and Ron close behind him.

Hermione was already seated again at the table, scribbling furiously. "Hermione!" Ron complained. "Will you please slow down and tell us what that was all about?"

Hermione set down her pen and held up her parchment triumphantly. "Remember what I just said about things striking us? Look at this!"

They stared at what she had written. Between the lines of the riddle she had added lines from her memory: Danger lies before you, while safety lies behind / Two of us will help you, whichever you would find...Fourth, the second left and the second on the right / Are twins once you taste them, though different at first sight. "See? The structure of the lines is exactly the same as the older puzzle, and even the rhymes are the same for the first and last couplets. That couldn't have been a coincidence."

Ron was shaking his head with a slightly bemused expression. "I can't believe you remembered that, Hermione."

Draco frowned. "But what does it mean?"

Hermione tapped her chin thoughtfully with her quill. "There are a lot of twos here—two paths, two will help you, second left and second right, twins.... So what else has Professor Snape told us about twos?"

"Two messages," Harry offered quietly. "One in the chess game and one in the riddle."

"You think that chess game was a message?" Draco challenged.

"Why not?" Harry replied. "'...twins once you taste them, though different at first sight.' Why put that game together so carefully if it's not supposed to tell us anything? If he'd just wanted us to win the game, he could've given us something much easier."

Ron jumped up and began to pace. "If it is, then we're in trouble," he muttered. "If that White Pawn was You-Know-Who, then it means that he's up to something would mean disaster for the rest of us. But we don't know where he is or how to find him. And then there was the attack on the Black King. If we don't defend against that, then we're dead anyway."

"So who's the Black King?" Draco asked.

"McGonagall," Harry replied immediately.

"We don't know that," Hermione hesitated. "It could be you, Harry. After all, the Prophecy has your name on it, not Professor McGonagall's. According to the Prophecy, we lose if we lose you."

Harry shook his head. "We lose if we lose McGonagall. She was the only one who could hold us all together after Albus died. If we lost her like we lost Albus, the Order, the Ministry—all of us would fall apart. Besides, if I'm going to fulfill the Prophecy, I'll need freedom of movement, and that's one thing the Black King doesn't have."

"It was the Black Rook who took the White Pawn," Ron tentatively agreed.

Hermione sighed. "But we can't know for sure."

"Se...Snape wouldn't have made me the Black King," Harry persisted stubbornly.

Ron shrugged. "That could be true, mate, but what does it tell us?"

"It sounds like Voldemort is going to attack Hogwarts," Draco suggested. "There're your two paths: Voldemort is planning something major while he uses an attack on Hogwarts as a decoy."

"'Danger lies before you, while safety lies behind'," Harry quoted. "So what lies before us?"

"That's probably what the rest of the riddle tells us, if we can figure it out," Hermione said.

They all stared down at the riddle in silence.

Ron resumed pacing furiously. "The man's mind is a bog," he muttered. "How in the name of Merlin does he expect us to be able to solve something like this?"

Harry, Hermione, and Draco exchanged slightly ironic glances. "You're the master of strategy," Draco drawled.

Ron stopped. "All right, fine," he said. "Let's look at this from a strategic point of view. If we're going to be able to attack Voldemort before he undergoes the transformation from Pawn to...whatever, we'll need at least four things: some idea of what Voldemort is planning, where he is, how we're going to get at him, and a timeframe to work with. Without those things we're just groping in the dark."

"What, where, how, when," Draco murmured.

"There are four lines here. Let's go through them out one at a time," Hermione suggested.

After a moment of silence, Harry looked up. Hermione's gaze was resting fixedly on a single spot on her parchment. "Hermione," he said softly, and her eyes lifted to meet his. "'The Merlin's Dance'...it has something to do with Mount Killaraus, doesn't it?"

Hermione bit her lower lip for a moment and nodded. "I didn't want to say it until you had figured it out for yourself, Harry, but...yes, I think it does. Though since Professor Snape mentions the Merlin, I think he means Stonehenge, not Killaraus itself."

Ron looked confusedly from Harry to Hermione and back again. "Killaraus? Stonehenge? Will you two please explain?" he demanded. "All I see here is old Merlin doing something I'd rather not be watching."

Hermione rolled her eyes. "Honestly, Ron, didn't you pay attention at all in Astronomy?"

"All I remember about star charts is that chaos follows when Venus and Mars are in the same house," he grinned at Hermione sheepishly.

Hermione sighed with exaggerated exasperation and turned to Draco. "Do tell me you know what we're talking about."

"I fell asleep even more in that class than I did in Divination," Draco shrugged. "I've always found the various gruesome deaths in Potter's future to be more interesting than little dots in the sky."

"Well, honestly," Hermione huffed. "Draco Malfoy, you, at least, should know this, given that 'Preserve Our Magical Heritage Society' your father founded," she said witheringly.

Draco held up his hands placatingly.

"Look. We know that Merlin built Stonehenge with stones transported from Mount Killaraus, right? Well, Killaraus is also sacred to the Giants because it is one of their special burial sites; the stones of Stonehenge were originally called 'the Giants' Dance'. So you could say that Stonehenge is 'Merlin's Dance'," Hermione explained.

"Merlin's Dance. That's brilliant!" Ron exclaimed. "But what about the 'a guide in darkness' part?"

"Well," Hermione frowned. "That's the part I'm not sure about. If it is Stonehenge, 'darkness' makes sense because the stones predict the movement of the stars. But somehow I think that that line refers to something more specific."

"...a guide in darkness o'er the Merlin's Dance takes flight..." Draco repeated thoughtfully.

"The North Star?" Harry suggested. "Sailors used it as their guide at night for navigation."

"That's probably it," Hermione allowed. "But...it just seems too obvious."

"Obvious?" Ron repeated incredulously.

"I mean, it doesn't seem to lead anywhere." Hermione worried the tip of her quill. "I can't help but think there should be something more." But after a moment she sighed and wrote down a note on her parchment. "All right, I suppose that's as close as we can get to an answer to the third line for now. Let's take the line above that—that seems rather obvious too, doesn't it?"

"Secrets of the Snake...the Chamber of Secrets!" Ron exclaimed.

"That must be the 'what' of Voldemort's plans," Harry observed. "Something in the Chamber is going to tell us Tom Riddle's moves."

"Then let's go." Hermione stood.

"No." Harry shook his head, and hid a wince at the pain that movement had caused him. "Hermione, you're the one with the best chance of solving the rest of the riddle. You and Ron should stay here and see if you can figure out anything else. Malfoy and I will search the Chamber of Secrets."

"All right," Hermione agreed. "Tell us as soon as you find anything."

Harry nodded. "Send Pig if you need us."

[[center:***]]

"But what could we find there?" Draco asked curiously as they sped through the corridors. "Hasn't the Ministry scoured the place once already?"

"Yeah," Harry frowned. "Seventh Year. Scrimgeour sent Aurors to search the place. They asked me to open it for them, but wouldn't let me follow them down there. Then they put wards over the entire place to lock everyone else out, but I don't think they found anything."

"What were they looking for?" Draco wondered.

"Power," Harry shrugged. "But maybe it died with the basilisk. Maybe there was only the basilisk. That's what the Ministry concluded."

"Snape seems not to think so," Draco commented. "What else do you know about the Chamber?"

"Only what McGonagall told us in Third Year about Slytherin creating it for his Heir. And that Voldemort used it while he was a student here, until Dumbledore grew too suspicious," Harry responded. "What about you?"

"Not much more," Draco replied. "Father knew about it, but didn't tell me much. He did say, though, that Slytherin left behind hints of very ancient, very powerful magics, and that it was there that You-Know-Who found the knowledge to create the Dark Marks."

"The Dark Marks...?" Harry pondered. "So there must have been something in the Chamber once upon a time. But even if there was, I don't think Riddle would've left it there for anyone to find."

They stepped off the staircase on the first floor and hurried down the hall. Harry had already retraced the familiar steps into Moaning Myrtle's bathroom and stopped in front of the sink before he realized that Draco was nowhere to be seen. He peered around the sink at the doorway and blinked at a peevish-looking Draco. "What?" he asked.

Draco replied, "Potter, you do realize you are standing in the middle of the girls' bathroom?"

Harry sighed and rolled his eyes. "Really. I hadn't noticed. Look, it's not my fault one of the four great founders of Hogwarts decided to put the entrance to his secret lair in the bloody girls' bathroom. Just be glad the Ministry persuaded Myrtle to move her haunt elsewhere. Now, are you coming or not?"

Draco reluctantly entered the room, all the while muttering under his breath about the affront to Malfoy family dignity.

Harry turned his attention to the snake engraved on the sink. "Open," he commanded in Parseltongue, and the sink slid apart to reveal the tunnel into Slytherin's Secret Chamber. He cast Levitation on himself and floated down to the bottom, his wand lighting the way. Draco landed beside him a moment later.

"Looks like the Ministry really wanted to keep people out," Harry commented, looking around at the multitude of wards blocking the way into the Chamber. "They'll know if we start blasting through these."

"Not that it matters," Draco pointed out. "We'll be one step ahead of them, anyway. They can't do anything to stop us."

"True," Harry acknowledged.

"So how did you manage to kill the basilisk?" Draco asked curiously. "I thought it was immune to most types of magic—and anyway, you couldn't have known that many spells then."

"Fawkes brought the Sorting Hat," Harry explained shortly, and muttered a splitting curse against the ward in front of him. "Hey, give me a hand with this, will you?"

"A Phoenix and a Sorting Hat—that explains everything," Draco drawled, but he went to work beside Harry.

"The Sorting Hat gave me Godric Gryffindor's sword, and I used that to kill the basilisk," Harry responded, before blasting a hole through the next two wards.

"Hold on—Godric Gryffindor's sword?" Draco asked. "Why would a wizard like Gryffindor need a sword? Did it have any magic?"

"To kill basilisks with, maybe," Harry shrugged. "It seemed like just an ordinary sword, though, no special magic that I could see."

"Too bad," Draco commented. "A magical sword might've been useful." He took down the next two wards, and they were through. "Huh."

The basilisk's body lay where Harry had slain it, curled before Slytherin's gigantic statue. Its flesh had decayed over the years to reveal the stark white bones beneath.

"Careful," Harry cautioned as Draco approached the long skeleton. "It may be poisonous."

Draco paused and turned to smirk in his direction. "It looks like the Ministry was good enough to contain it for our benefit. Look, there are wards all over the bones. Though I wish they could've done something about the smell. Government idiots."

Harry rolled his eyes. "If you want to waste magic on something like that, be my guest." He stopped next to Draco and looked down at the sprawling, massive skeleton reaching up to his waist. "Hold on. There's something missing. It looks like the Aurors took the basilisk's scales. They wouldn't have dissolved, right?"

"The scales?" Draco repeated, puzzled. "What would they want with that?"

Harry frowned. "I don't know... Maybe they thought it held some kind of clue to Slytherin's secrets. Maybe they used it for Potions ingredients." He wandered over to the statue at the front of the Chamber. "What do you know about Salazar Slytherin?"

"Other than that he was the most powerful wizard of his age?" Harry snorted, but Draco went on, "Not much else that could actually be verified. His parents were pure-bloods, but when his father died, his mother married a Muggle, and they lived as Muggles. He had a step-brother who was born with magic, but rejected his wizarding heritage—remember that this was when Muggles persecuted wizarding folk. Anyway, this step-brother later betrayed Slytherin to the Muggles, and he had to run so that he wouldn't be burned at the stake, or whatever it was those Muggle barbarians did back then. No one knows what he did between that time and when he met the other three Founders to build Hogwarts, but he supposedly had knowledge of magics that were very ancient and very powerful."

"Knowledge that he then passed onto his Heir, Voldemort. Or Tom Riddle, at the time," Harry added. "Don't you think it's rather ironic that if Slytherin had had his way about not allowing Muggle-born children to enter the school, his lasting descendant would never have been admitted?"

"...and the world would have been a better place, and Slytherin would've been right anyway?" Draco supplied.

Harry rolled his eyes, then craned his head back to look at the face of the statue. He shivered slightly at the darkness beyond the open mouth, though he knew that the basilisk was dead. "I wonder..." he murmured quietly to himself, and gripped his wand tightly, feeling the fine grain of the handle digging into his fingers.

He cast a Levitation spell on himself and floated upwards. "Lumos!" he said, and light shined into the dark cavity. He stared for a moment, puzzled, then called, "Hey Malfoy, take a look at this."

"What am I supposed to be seeing?" Draco asked as he floated to Harry's side.

"Look at the dust," Harry replied quickly.

"Dust," Draco repeated blankly. "There a lot of it."

"No, there a pattern to it, see?" Harry pointed to the concentric depressions in the dust coiled around the center of the tongue.

Draco squinted. "It looks like...the basilisk may have been guarding something?"

Harry waved his wand back and forth across the statue's mouth. "Yeah. But whatever it is, it's long gone," he sighed. But as he turned to go, a small glint of reflected light between the tongue and teeth caught his attention. He pointed his wand at it. "Accio!" Something flat and hard and smooth sailed into his hand.

He turned it over and over again, then held it up for Draco to see. It was shaped like the single petal of a clover leaf and small enough to fit on his thumb. Harry wasn't surprised that the Aurors had missed it. "It looks like..."

"...a scale," Draco finished. "The basilisk's?"

"No...I don't think so..." Harry replied, running the tip of a finger over the mirror-smooth, ebony surface. When he moved the scale, the light that shimmered across it was a deep amethyst, not the white of his wand-light. "The basilisk's scales were gray," he recalled. "This is...something else. A dragon's scale, maybe?"

Draco considered. "I'm no expert on dragons, but I don't think Hebridean black dragons' scales look like that.

"Maybe it's supposed to be a clue—something left by Slytherin," Harry suggested. "Or another riddle." He held up the scale. "Dragon," he said to it. "Riddle. Snake. Key." He turned the scale over, catching flashes of amethyst light across its flowing surface. "Slytherin. Book." He shrugged at Draco helplessly. "Dammit. We need more information."

"The Restricted Section?" Draco suggested.

Harry shook his head. "No, something better. Let's visit Snape's library."