I do not own Harry Potter.

...

His message made McGonagall lean back in her chair and consider his words.

"I trust you, Mr. Potter, and I certainly can't leave you on your own to defeat someone like You-Know-Who. However, your words are a trifle alarming. I cannot imagine why you would even mention Parselmagic. Were you aware that it is dark magic?"

"I am fully aware of the status of Parselmagic and Parselmouths, Headmistress. In fact, this is why I need your trust. Tell me, what do you remember of my second year? Five years ago?"

"Well, it would be a hard year for me to forget. The Chamber of Secrets was opened, as you well know. You defeated the basilisk after finding the Chamber."

"Dumbledore placed a mass memory charm on the inhabitants of the castle at the end of second year. Apparently, it covered the staff as well as the students." He showed the message to McGonagall, preparing to write. A lot.

"What…what happened that he needed to cover up?" McGonagall asked, seemingly a little shocked.

"You remember that dueling club that Lockheart started? I was revealed as a Parselmouth in a duel when Malfoy conjured a snake. The whole school thought that I was the Heir of Slytherin because of it."

McGonagall read his message with wide eyes.

"I…remember now. Quite a few of the staff were wary that you were becoming a dark wizard."

"I was never a dark wizard; I can't help that I have the Parseltongue genes."

"Of course. However, why is this relevant? You are still a mute."

"I can still speak Parseltongue."

That message caused McGonagall to be silent for a moment.

"Why? I thought that your vocal chords were burned away."

"They were…at least my human ones. Apparently, I have three passages in my neck instead of two – the two that everyone has in addition to one with a serpent's vocal chords. Muscles control which set of vocal chords are being used."

"And how do you know this?"

Harry looked at his lap sheepishly, before writing his response.

"A snake told me. He was the son of Voldemort's familiar, Nagini. Voldemort was the one who'd done the research on Parselmouths."

Again, McGonagall was stunned.

"I want to master Parselmagic. I don't know how far Voldemort has gone with it, but I'm certain that he has investigated it. If I can manage it, it will help to put me on an even footing with Voldemort."

"How do you intend to study it? All books on the subject have been confiscated by the ministry."

"I have a book on it. Hermione bought it for me, I'm guessing in Knockturn Alley. I also will have access to the library in the Black ancestral home, which has many books on dark magic. I am hoping to find a book on Parselmagic there."

"Well, Mr. Potter, you seem very well prepared to me. However, I advise you not to let anyone else know of your Parseltongue abilities. You never know what the ministry would do."

"I never intended to, Headmistress."

"If you want my help, I'm not really sure what I can offer you. I am not as powerful, nor as wise as Dumbledore. I believe you have far surpassed me in magical power, as well."

"Actually, there is something you can do." Harry wrote. The time had come where help was needed. His heart began to pound as he wrote his next sentence – he was putting his absolute trust in the headmistress; no secrets now. "Do you know anything about horcruxes?"

"I have heard of them, but only know that they are the very darkest magic and hold a fragment of a soul."

"Voldemort has created horcruxes. Seven, Dumbledore believed. Dumbledore also thought that Voldemort targeted objects that used to belong to the founders to make his horcruxes. We know that two of them have been destroyed already, the diary I brought from the Chamber of Secrets, and the cursed ring that Dumbledore had last year. We know of two others, as well. One is what Dumbledore and I went searching for at the end of last year – a locket belonging to Slytherin. The locket, when I retrieved it from Dumbledore's body, turned out to be a fake. Someone named 'R.A.B.' stole the real one and replaced it with a replica. The other one we know of is a cup belonging to Hufflepuff. It was stolen by Voldemort after he murdered its owner, Hepzibah Smith, and has been missing ever since."

"Am I right to presume that your mission from Dumbledore is to track down these…things…and to destroy them?"

"Yes. Hermione, Ron, and I have made a list of objects that we suspect Voldemort would target to make horcruxes, and a list of locations where he may have hidden them. We hope to start looking soon."

"Two were destroyed, you said? Leaving five?" Harry nodded. "And you know what two of them are, leaving three?" Again, Harry nodded. "What other items do you suspect?"

"There is a diadem that used to belong to Rowena Ravenclaw. It went missing after Helena Ravenclaw stole it and fled to Albania."

"And Albania was where You-Know-Who was hiding," McGonagall said, connecting the dots. Harry nodded.

"What about Gryffindor? You said that You-Know-Who was collecting an object from each founder."

"We didn't find any notable objects that Gryffindor left behind, apart from his sword. We do not think that the sword is a horcrux, however, as when I used it in the Chamber there was no dark magic surrounding it, and it was been in Dumbledore's office for years."

McGonagall nodded in agreement.

"I cannot argue with your reasoning, Mr. Potter. Does this mean that you have no idea what the other two objects are?"

Harry shook his head, and McGonagall became quiet, thinking.

"Did You-Know-Who wish to create seven horcruxes, or seven parts to his soul?" McGonagall asked. Harry shot her a puzzled expression.

"If he wished to create seven horcruxes, then there would be eight parts to his soul, as one part still would reside in him. However, if he wished to create seven parts to his soul, there would only be six horcruxes."

Harry did the mental tallying and realized that McGonagall was right. How had they overlooked this?

"He wished to make seven soul pieces. This means that we are closer than we thought!"

McGonagall gave him a small smile, happy that she had helped, even though it was in a small way.

"What about the places where they may be hidden?"

"Voldemort seemed to like hiding them in places significant to his past. The ring was in his grandfather's house, and the fake locket was in the cave where he tortured his first victims. I don't know where the diary was – though I suspect that Lucius Malfoy was the one who smuggled it into Hogwarts, I have no idea where he got it from. We think that Voldemort may have hidden horcruxes in Godric's Hollow, Riddle Manor, Borgin and Burkes, the orphanage where he grew up, and Hogwarts."

"Hogwarts?" McGonagall asked. It looked as if her mouth had gone dry. Harry nodded solemnly. "Why?"

"He hated his orphanage. He considered Hogwarts his home, and it would stoke his ego to have hidden something like a horcrux right under Dumbledore's nose."

"Again, I can see no fault in your reasoning, which is what worries me. Surely if there was something as dark as a horcrux in Hogwarts, someone would have noticed by now?"

"Hogwarts is a huge castle, Headmistress, with many secret rooms and passages. There are so many places that are not frequented regularly; it would not surprise me if Voldemort had managed to hide a horcrux here."

McGonagall sighed.

"Am I to assume you will be searching Hogwarts for this horcrux first, as it is the easiest to access?" Harry nodded. "Unfortunately, I do not know the hidden ways of the school as well as I could. All I can offer are these," McGonagall wrote something on a piece of parchment, and then duplicated it twice so that there were three of them. She handed them to Harry.

"Although I do not advise that you go walking around the school after curfew without trying to hide it, those are passes that will keep you from getting into trouble should you be spotted. Please make sure you get enough sleep."

"Thank you, Headmistress."

"Come to me if you need anything else."

Harry stood and stretched his muscles, then cast a tempus. He hadn't realized it, but he and McGonagall had been talking for nearly two hours.

"Just one last thing, Headmistress. You don't have any idea who R.A.B. is, do you?"Harry wrote.

"I'm afraid not, Mr. Potter. If I hear of someone who has those initials, I will tell you. I will keep this entire discussion a secret, of course."

Harry nodded, and gave McGonagall a small smile to show his gratefulness.

"Goodnight, Mr. Potter."

Harry nodded, slinging his book bag over his shoulder. He had ten minutes left before curfew.

The next morning – a Saturday - Harry filled both Ron and Hermione in on the conversation he'd had with McGonagall and gave them each one of the passes the headmistress had provided him with.

"This is great, Harry!" Hermione said. "We can also use our prefect patrols as another excuse."

"Where do you think we should look first?" Ron asked.

"The best plan I have right now is to search the castle, floor by floor."

"That will take ages!" Ron protested.

"I know."Harry signed, his shoulders slumped.

"Well he wouldn't have been able to hide anything in the areas where people go regularly." Hermione pointed out. "That means that the library, Great Hall, Entrance Hall, and common rooms, and dorms are out."

"Oh, bloody brilliant. That still leaves most of the school! Seven floors and the dungeons, not counting the grounds and towers!" Ron said. Hermione ignored him, instead turning to Harry.

"What places in Hogwarts would have been special to Voldemort?"

Harry scratched his head, processing the information he knew about Tom Riddle's time in Hogwarts.

"He was close to Professor Slughorn, though I don't think he would have managed to hide anything in the Professor's office or the potions classroom. The only other thing I know about him at Hogwarts was that he was a prefect."

"That's not very helpful." Ron complained. Harry shrugged.

"Why don't you look over the Marauder's Map? Maybe you'll find a room that is a likely hiding spot." Hermione suggested.

"Alright." Harry signed, resigned that there weren't many other options at the time.

"In the meantime, I'm going to research Unbreakable Vows." Hermione continued. "Maybe I can figure out some way to break them."

"I don't think that's possible. I mean, they're called Unbreakable Vows for a reason, Hermione." Ron said. Harry nodded in agreement.

Hermione shrugged. "If I can find out how they work, then maybe I can figure out how to make them break. It's worth a try, and shouldn't take too long."

"If Harry's going to be looking over the Marauder's Map, and you're going to be researching vows, then what will I do?" Ron asked.

Hermione's grin was positively frightening.

"I don't know why I should be writing this essay, it isn't even due for another four days…" Ron grumbled.

Harry huffed quietly without looking up from his own subject of study, the Marauder's Map. Ron took this as agreement, and continued.

"I mean, it's not as if I really need to do it yet. Why Hermione makes me do homework nearly a week before it's due is a mystery."

Harry finally looked up, accepting that Ron wanted to turn this into a conversation.

"You know she can't actually make you do anything."Harry pointed out. Ron seemed at a loss for words for a minute.

"Hey…you're right. You know, I think I'll just go get that Muggle magazine my dad gave me before we left…"

"What was that, Ron?" Hermione asked in a honeyed tone, coming up to their table in the common room. The red-head gulped.

"Err…I was just asking Harry about something for my essay." Ron lied. Harry could have sworn that he saw a glimmer of sweat on his friend's brow.

"And what was your question, Ronald?" Hermione asked, still in that honey-soaked voice.

Ron glanced quickly down at his essay, trying to come up with a suitable lie.

"Erm…what is the best way to harvest tentacula leaves?" Ron said. Hermione raised an eyebrow, casting her own eye over his essay.

"I see. And why do you need to ask that for a potions essay?"

Ron looked desperately at Harry, seeking back-up. Harry just shook his head. Ron was on his own.

"I was just…curious?" Ron said, trying his excuse out. Then he decided it was a good excuse, apparently, because he repeated it, in a firmer tone: "I was just curious."

"I see. Then you won't mind finishing the essay today, will you?"

"Err…I guess not." Ron said, defeated. Hermione smiled triumphantly, and then turned to Harry.

"Actually, I came back to the common room because I found something."

Harry raised his eyebrow, inviting her to continue.

"Unbreakable vows are linked to your magical core. The details weren't specified, but the vow actually uses a portion of your own magic to kill you if a set of conditions determined by the individual vow are broken." Hermione explained.

"Bloody brilliant. How will that help us?" Ron asked. Hermione turned her disapproving gaze onto the red-head.

"If we can find out how it is linked to Harry's core, maybe Harry can find his core again and dismantle the vow."

Ron's mouth dropped open.

"But Unbreakable Vows are…well, unbreakable! You're saying Harry could just go in and get rid of it?"

"Theoretically. Of course, I don't expect it would be easy, and it will probably take a while to find the right information so that Harry would be prepared to try. I'm going to be doing further research on the vow, Harry, but I'll also look for other methods that you could use to communicate."

"Couldn't I just find my core again and try to do it? I mean, we know that it is linked to my core. Wouldn't I be able to figure it out?"Harry asked.

"No! You don't understand. Magical cores are extremely volatile. That is why it is so dangerous to link with one. If you did something wrong, you could end up a squib, or disabled, or even dead. With the right provocation, magical cores explode, possibly destroying the wizard as well as causing mass damage to their surroundings. You can't mess with it, Harry." Hermione said.

"Alright, I get it. I won't do anything stupid, I promise."Harry soothed. Hermione sighed with relief.

"Good. How's the examination of the map going?" she asked.

"Haven't found anything, really. I know most of the passages and rooms on here." Harry signed.

"Well, keep looking. You never know." Hermione said. "I'm going back to the library. I'll meet you in the great hall for lunch. Make sure that essay gets finished, Ron."

Ron groaned after Hermione left.

"Why do I listen to her?" Ron asked, mostly to himself.

"Because she scares you?" Harry asked innocently.

"She does not scare me. She can just be…intimidating."

"Yeah. I guess I know what you mean."