By the time Harry, Snape and Ginny arrived in Dumbledore's office, Sirius had already Flooed through with Remus, and the pair of them, were waiting impatiently with Dumbledore and McGonagall.

Harry's expression, which had been grim and nervous when he walked in, eased slightly when he saw Sirius, but he didn't run forward to stand with him, as Sirius had expected. Instead, he stayed by Ginny, who looked so scared that Sirius thought she might be sick.

"Verification by letter would have done it," Snape drawled.

"The fact that you even needed it means something's up," Sirius replied, folding his arms. He tried to catch Harry's eye, but Harry was looking at the floor. "I thought it was best to play it safe." Next to him, Remus nodded. Dumbledore cleared his throat gently, but Sirius could smell his worry, and his impatience.

Before Snape could explain anything, though, there was a sniff, and a shuffling sound, and Filch appeared in the doorway to the office, cradling his cat.

"They attacked her, Headmaster," he croaked. Sirius almost chuckled – Filch's cats had never been popular with the students – but the way Harry shrank back changed Sirius' mind at once. Ginny, looked like she might cry. This time, Sirius was able to catch Harry's eye, and was surprised when Harry's expression changed from scared to pleading. "They-"

"I'm not familiar with her condition," Snape said curtly. "But she isn't dead." Dumbledore was on his feet, and over by Filch and the cat in moments. He ran his hand over her, murmuring into his beard, and then stepped away.

"Petrified," he murmured, and shared a look with McGonagall, who also looked grim.

Petrified? Sirius wondered, frowning at Remus, who shrugged.

"She was found by a message," Snape continued, with a fleeting look at Harry and Ginny. "'The Chamber of Secrets has been opened. Enemies of the Heir, beware. I've-" Snape hesitated. "To my knowledge, such things were rumours." Confused, Sirius glanced at Remus who shrugged and shook his head. Dumbledore's eyes closed for just a moment. Then they opened.

"And Harry and Miss Weasley?" Snape looked annoyed that Dumbledore hadn't said more about the mysterious chamber.

"They did it!" Filch said.

"We didn't," Ginny said, speaking for the first time. "I promise, we only found her that way-"

"Neither were at the feast," Snape said, after a moment.

"Miss Weasley?" McGonagall said.

"I was asleep," Ginny said. "And then I woke up and Harry and I were going to go down to the feast, only…" She cast a nervous glance in Filch's direction, and he bared his teeth at her, and hugged his cat more tightly. Dumbledore nodded at Ginny, and glanced at Harry.

"I was with Padfoot and Moony," Harry said. "It's- well, it's Halloween, so-"

"I wasn't notified of your presence on the grounds," Dumbledore said, giving bot Sirius and Remus a piercing look.

"We weren't on the grounds," Sirius said.

"Hogsmeade," Remus added, looking a bit sheepish.

"With Mr Potter?" McGonagall's nostrils flared. "We weren't notified-"

"I'm an Auror and Remus is a teacher," Sirius said. "And I'm his guardian on top of all of that."

"The fact remains, Mr Black, that we have a duty of care," she said curtly. "And, were he not already present, Mr Potter is among the first students I would be checking on, given his-" She glanced at Harry and her mouth thinned. "-well, given who he is and his tendency to get himself and – my apologies, Potter – others, into dangerous situations." Harry was looking at the ground again, but Sirius still saw his face redden.

Sirius couldn't quite fault her logic, much as he wanted to.

"Harry was with us," Remus said quietly, "notice - or lack of it - aside."

"And when you returned, why did you go to Gryffindor tower?"

"Peeves," was all Harry said, and Sirius wasn't the only one that grimaced.

"I do not," Snape said into the silence that followed, "believe that either of them are responsible."

"Obviously," McGonagall said. "The question is, who is responsible?"

"I know what you're thinking, Minerva, but I do not believe that the person-" His eyes flicked around the room. "-that was blamed last time-"

"I don't believe that any more than you do, Albus," McGonagall dismissively. "Aside from anything else, I sat next to him tonight, and comforted him about his dead roosters."

"Roosters?" Ginny asked. McGonagall waved a hand at her.

"Did either of you happen to see or hear anything?" Dumbledore asked.

"Nothing," Ginny said at once, shaking her head.

Sirius wasn't surprised – but his heart sank anyway – when he looked at Harry and saw him biting his lip.

"I- erm- I might have." He looked at Sirius and muttered, "I heard the voice again."

"So you've heard this voice twice now?" Dumbledore asked. The intensity of his stare made Harry feel like he was the only one in the room. He nodded. "And neither Mr Weasley or Peeves, who were with you on these occasions, gave any indication that they could also hear it?"

"No," Harry said. Dumbledore steepled his hands.

"Forgive me for asking, Harry, but has your scar been troubling you of late?"

"No," Harry said again. Ginny shifted next to him, and Harry thought she was holding herself together remarkably well.

"Severus-"

"Nothing," he said, and Harry didn't miss the way his hand moved, as if to touch his arm. Dumbledore leaned back in his chair.

"Well," he said after a moment. "It seems there's little more we can accomplish today. Argus, if you will leave Mrs Norris in my care, I'll have her kept safe until she can be given the mandrake restorative. Minerva, you will go to Filius and tell him what has happened here, Severus, you will go to Pomona." The three of them left the office, Filch far less briskly than the teachers.

"Sir," Harry said, "what's the Chamber of Secrets?" For a moment, Harry thought Dumbledore might not answer. Then, with a glance at Padfoot and Moony, he sighed.

"It is considered to be a legend only, except by those who know better." There was no twinkle in Dumbledore's eye, and he sighed before continuing. "As I'm sure you all know, Hogwarts was founded by those that our Houses are named after: Gryffindor-" Dumbledore nodded at the four of them. "-Hufflepuff, Ravenclaw, and, of course, Slytherin."

"Perhaps it will not come as a surprise, that Salazar Slytherin disliked muggleborns. Over this matter of opinion, he and the other Founders quarrelled, and Slytherin was driven from the school. And this is where the Chamber of Secrets comes in; it is rumoured that, before he left, Slytherin created a secret chamber, within which dwelled a monster that he intended to have purge the school of those with anything less than the purest of heritage."

"But it's not a rumour?" Padfoot asked, frowning.

"The Chamber of Secrets was opened fifty years ago, when I was the Transfiguration teacher here at Hogwarts."

"With Headmaster Dippet," Ginny said. Dumbledore looked surprised, but nodded; other than Dumbledore, and one of Padfoot's ancestors, he had no idea about the lineage of the Headmasters. Perhaps Ginny had been spending too much time with Percy. Dumbledore waved his hand at a portrait, who nodded back, looking grim, and Harry assumed that he was Dippet.

"Everything started much the same, last time; there was an attack, and a warning-"

"How did it end?" Harry asked.

"After several more attacks, a student was killed." Dumbledore's voice was sad, and Fawkes, who'd been silent the whole time, trilled gently. "After that, a culprit was found, and while the attacks stopped, I, personally do not believe that that person was responsible." Ginny squeaked.

"Who-"

"It is not my place to share," Dumbledore said gently. "What I can and will share is that we searched the school top to bottom, and never found any evidence of the Chamber, or of the monster."

"Other than the attacks." Moony's face was grim.

"Other than the attacks," Dumbledore agreed gravely.

"If it wasn't the person that was caught," Padfoot said slowly, "who did you think it was?"

"I had one suspect," Dumbledore admitted, "who would have fit all of the criteria except for the fact that he had a muggle father, and a mother that may or may not have been a witch, but, most significantly, no evidence of a connection - that I have been able to find - to Slytherin's line."

"He, sir?" Harry asked.

"Voldemort, Harry," Dumbledore said.

"He was at the school back then?" Ginny asked, eyes wide. She no longer seemed scared, just intrigued.

"He was," Dumbledore said. "But, both Harry and Severus are… sensitive to his presence, and I have reason to believe that would also be the case in this instance, were he involved."

"But we can't rule him out," Padfoot said.

"Can we ever?" Harry asked unhappily.

"I will," Dumbledore said after a moment, "prepare an address to be given to the school at breakfast. I would appreciate your discretion-" He looked at Harry, then at Ginny. "-in the matter until then."

"Yes, sir," Harry said, and Ginny nodded.

"Very well," Dumbledore said, getting to his feet. "Remus, I hope the new position is going well. I'm just sorry we couldn't have met up under better circumstances."

"Me too," Moony said, reaching forward to clasp Dumbledore's hand.

"And Sirius," Dumbledore said, with a half-sigh, half-smile, "I imagine I'll be seeing you regularly until things have settled."

"Yep," Padfoot said.

"I would appreciate it if you leave me to handle matters in my school, however," Dumbledore said. "Last year should be evidence enough that if I need the Aurors' help, I shall ask for it."

"Understood," Padfoot said, nodding.

"Now, I think it's about time you two were back with your friends and family, in your House," Dumbledore said, clasping his hands. Harry nudged Ginny toward the door. Ginny was a pureblood, and Harry himself a half-blood, so they should be safe, but Harry almost asked if Padfoot and Moony would go with them anyway. "But not alone," Dumbledore continued. "Not tonight." Harry relaxed slightly. "And, since I've sent Minerva away to do other things, I suppose the position of escort falls to me." Ginny looked startled, but relieved.

Harry hugged Padfoot and Moony goodbye, and watched them vanish into the fire as Dumbledore guided them toward the stairs.

Ginny wasn't at all surprised when they arrived back in the common room – Dumbledore had bid them goodbye at the portrait – and found Ron, Hermione and Draco waiting for them. News had obviously spread; everyone seemed to be watching them, and she wondered if this was what it was like to be Harry. She didn't like it much at all. Percy and the twins seemed to be doing a good job of keeping everyone away, though, and within seconds, Hermione had thrown her arms around Harry, and Ron had descended on Ginny and the five of them were safely tucked away in the second year boys' dormitory.

Neville was the only one who'd been in there, and he'd taken one look at them and made an excuse about going back down to the common room. The five of them squeezed onto Ron's bed and Ginny found herself wedged between Ron and Hermione, feeling very safe despite what had happened.

"What happened down there?" Hermione asked. "Draco's been telling us about the Chamber of Secrets-"

"You know about it?" Ginny asked him.

"My father used to tell it as a bedtime story," Draco said, his cheeks faintly pink. "Nothing like hearing about Slytherin's monster attacking muggleborns to put Hydrus to sleep." Ginny knew he wasn't joking, and grimaced. They swapped stories quickly; Draco's account was much the same as Dumbledore's, down to not knowing who was responsible, where the chamber was, or what the monster was. "I've been thinking, though, Potter," he said. "If you're the only one that can hear it… what if it's a Kelpie?"

"What?" Ron asked. Hermione shrugged at him, but Harry's mouth had fallen open.

"Do you think?" Harry asked, eyes wide. "It would make sense; if it was a Kelpie, it could live in the lake, and they'd never find it in there… And it would explain why no one's seen it; Kelpies can change shape. Who'd give a mouse a second look, when they're after a monster? And there was water on the floor, Ginny! Maybe it came up through the toilet from the lake, and attacked Mrs Norris-" Ginny glanced in the direction of the ajar bathroom door, and didn't feel quite as safe as earlier.

"But what about the Chamber?" Hermione asked. "Both Draco and Dumbledore have said that the Chamber has to be opened before the monster can be released… How do you open the lake?"

"Maybe it's in the boathouse, or there's a secret passage," Draco said.

"Merlin knows there are enough passages on the map," Harry said. "They could have missed one, surely."

"Or maybe they just open the pipes," Ron said, shrugging.

"What about Petrifying people though?" Ginny asked. Everyone turned to look at her. "Do Kelpies do that?" Harry looked straight to Draco, who shrugged.

"I don't think so, but- maybe this one's special?"

"We need the library," Hermione said, nodding.

"You're not going anywhere," Draco said, waggling a finger at her. "Not tonight, anyway."

"And why not?" Hermione demanded.

"Weren't you listening, Granger?" he asked, exasperated. "Slytherin's monster goes after muggleborns-"

"Oh," she said. "Right, yes, but-"

"Write a list," Ron said, tossing a bit of parchment at her. "Malfoy and I can go-"

"What about-"

"Please, Potter, you're you. You're staying here, where the entirety of Gryffindor can watch you." Harry glowered at Draco, but Draco just folded his arms and stared back, until Harry sighed.

"Take the cloak." Harry slid off the bed and pulled a length of fabric out of his trunk. "And the map. If it is a Kelpie coming from the lake through the pipes, then you should try to avoid bathrooms." This time, Ginny wasn't the only one that looked at the boys' bathroom door.

"Right," Draco said, nodding. "Merlin, Granger, how are we supposed to carry all of that?" He snatched up the list and read it aloud. "Prophets from 1942, books about Kelpies, books about Slytherin- You too, Potter- really? You want that?" Harry had just added Nature's Nobility to the list.

"The Slytherin line ought to be well documented," Harry said, shrugging. "I'm sure people have looked before, but- well, it can't hurt, can it?"

Hermione finished her list, and then Ron and Draco left.

"Do you think they'll be all right?" Ginny asked.

"Of course," Hermione said. "You heard Draco; they're both purebloods." But Harry looked at Ginny and she knew he was thinking that the pair of them were blood traitors, as well.

"I think I might go to bed," Ginny said some time later, when it became apparent that Harry and Hermione intended to sit there in silence, waiting for the others to get back. "If something happens, come and get me, all right?" She didn't know what she, a first year, could do, but she'd want to help anyway.

"Of course," Hermione said, smiling at her. She squeezed Ginny's shoulders and moved so that Ginny could get up.

"Night, Ginny," Harry said quietly.

"Night," Ginny replied.

Ten minutes later, she was settled in bed, hidden by the hangings, with a quill in her hand, and Tom's diary in her lap.

Tom?

Ginny. She could imagine his pleased smile, and it made her want to smile too. How was the feast?

I didn't go. Tom, when you said things were bad when you were at school, were you talking about the Chamber of Secrets?

How did you know that?

Because it's happening again, Tom! Mrs Norris was attacked. Harry and I found her on our way downstairs.

Do they know who's doing it?

No. Ginny hesitated. But Tom, you were wrong. Dumbledore says the person you caught didn't do it.

Of course they did, Ginny, Tom replied.

No, Ginny wrote. Besides, you told me that Slytherin's descendant was still there after you 'caught' the culprit. That Slytherin's descendent is the one who trapped you in there.

I don't think I did-

You did, I remember!

Ginny-

Tom, you have to tell me who it was! Don't you see? They're here now, and I don't know if it's the same person, or one of their descendants, but I do know that people are going to get hurt if they're not stopped. And they might know a way to get you out of the diary-

Ginny, this is a lot to process, Tom wrote. His writing was shaky, and she felt immediately guilty for upsetting him. And- well, I've spent so long trying to forget about Slytherin's descendant that I don't know if I can remember his name… Time's different here in the diary, and it's been fifty long years-

I know, I know, I'm sorry to have to ask so much, but we can fix it!

I'll-I have to go now, Ginny. You've given me lots to think about, and I need time to try to remember.

Of course, Tom, I'm sorry-

Don't be sorry. You're such a kind, brave girl, and so clever to realise my mistake. My sweet Ginny. Ginny felt colour rising in her cheeks, and was thankful that she wasn't in the diary, where Tom could see it. Can you do me one favour, and not tell anyone about what I know? I don't think I could stand that pressure.

I won't say anything, Ginny promised.

Tom watched Ginny's goodnight message fade into the page of the diary on the table next to him, and threw his quill down, swearing.