A/N: This starts about a week in of Harry's sixth year. Snape and Narcissa never made the Unbreakable Vow; and the Trio knows what the Horcruxes are.
Disclaimer: I am not J.K. Rowling; I in no way own any of these characters or places.
"You see, sometimes the way things will work out is not always what is your first choice." Dumbledore paused before speaking again, looking over his half-moon spectacles. "I have found a way to defeat Voldemort." The old wizard stroked Fawkes absentmindedly as he waited for their response. He had called Harry, Ron, and Hermione in the middle of the night to ensure there would be privacy, because it was vital that the matter at hand be a secret.
Harry did not say anything, but looked at the Headmaster with wide eyes. Then he seemed to compose himself, and asked, "But what about the Horcruxes? Can Voldemort die if only two of his six Horcruxes are destroyed?"
"Seven," corrected Ron, "because the piece of soul that is still in his body. What is left of his soul, I mean. Wait, does that count?"
"No, Ronald. You make a Horcrux. Voldemort did not make his soul when he was Riddle. However, he indeed made seven Horcruxes, splitting his soul into eight parts, though he did not mean to make the seventh. The Horcruxes are all in this room now." Dumbledore indicated to the objects on his desk.
First, Tom Riddle's diary, with a hole in the middle of it made from the basilisk's fang. Next was Marvolo Gaunt's ring, with a black stone set inside the pierced gold.
There were four other items next to the Horcruxes. One, what was once a cup shattered into many pieces lying on the desk. Another, a pierced locket. A discolored diadem broken in half, presumably with Gryffindor's sword, lay next to the rotted body of a huge snake, with its head severed from its body.
Hermione counted them silently. "There are only six of the seven Horcruxes here. Where is the last one?" She inquired, counting them again but still coming up with the same result.
"Ah," Dumbledore said. "You really are the brightest girl of your age. You see, at the night at Godric's Hollow, when the spell backfired, Voldemort was destroyed." He paused to take a breath.
"We know that already!" Ron interrupted. "Tell us something we do not know, or let us go back to bed!"
"As I was saying," Dumbledore continued, ignoring Ron, "Voldemort was destroyed. After that, a piece of his soul broke off and went into you. This is why you could see into his mind, Harry, and speak Parseltongue. He cannot die if that fragment of soul is still in you."
Hermione gasped. "How do we get rid of it?" She asked desperately. "We can't use the Sword or basilisk fang, can we?" She looked at Harry with concern in her face.
"No." Dumbledore stated gravely. "But there is something that can kill that part of soul. I am not entirely sure it works. Are you willing to take the risk?"
"What do we have to do?" Harry asked with a trace of worry in his voice.
"The killing curse is the only thing to do. Are you willing to try it? Because otherwise, then Voldemort will live forever, just as he intended to do." Dumbledore looked judgingly at the body of the snake. "That thing smells horrid," He muttered. "Incendo." The snake burst into flames, leaving a pile of ashes on the desk.
"I'll do it." Harry said.
"Harry, you can't do this!" Hermione cried. "You might die with the Horcrux!"
"Look, Hermione, it's the only way. If I do not do this, Voldemort will be immortal. Do you want that? Because I certainly do not want him to kill more innocent people!"
She sighed. "Fine, Harry. But be safe. Promise me that."
"I promise."
Ron leaned forward in his chair. "Professor, wouldn't it help us if you told us the plan?" He asked.
Dumbledore smiled. "Ah, yes. Indeed, it would. First, it involves Professor Slughorn brewing a rather… special potion. I am not going to tell you what is in this potion, because it will ruin the… surprise.
"Then, you, Harry, will lead the Death Eaters and Voldemort outside of where they are staying in Malfoy Manor. Meanwhile, the two of you," he indicated Ron and Hermione, and one other will put two drops of the potion in each Death Eater's, but not Voldemort's, drink."
"But what happens if we get caught?" Hermione questioned. "And do we get to choose who the third person is?"
"You have pinpointed what I was just about to say." Dumbledore said. "Who would each of you choose, and why?"
Harry thought for a moment, and then answered. "I'd say… Ginny."
Ron glared at him. "Why my sister?"
"Because she is great at sports, can fight for herself, and… she probably would want to come along with us."
Ron glanced at him critically before saying what he thought. "Neville, because people would underestimate him. But he can fight pretty hard."
Hermione rolled her eyes at him. "How about Luna?" She asked.
"Why Loony?" Ron snorted.
"Exactly. People do not know her very well, and they underestimate her because she believes in things they do not. She also can confuse them with her talk of Nargles and Wrackspurts and other things."
"Interesting choices," observed Dumbledore. "Would you pick someone you dislike to go with you?"
"No!" All three yelled simultaneously.
"Indeed. But again, what would Voldemort do if you were there with an enemy?" He asked.
"He'd think the enemy was trying to stop us, and not suspect the enemy was working with us?" Hermione wondered.
"Precisely. That is why I have already chosen a fourth, member for your party. They should be arriving right… now."
There was a sharp knock on the door, repeated three times. "Professor Dumbledore?" Said Professor McGonagall.
"McGonagall? She's the fourth member?" Asked Harry.
"Come in, Minerva." Dumbledore called.
McGonagall came in first, followed by the fourth member.
"What's this all about, waking me up at past midnight?" He muttered. "Wait untill my father hears about this."
Ron smiled. "Did you forget that your father, in fact, is in Azkaban right now?"
"Filthy blood traitor. What am I doing here, Professor?"
Dumbledore sighed. "We want your help on a mission to defeat Voldemort."
"Why should I help people who are in Gryffindor, who are also Mudbloods and blood traitors? Most of all, why should I help Potter?
"Draco Malfoy, I feel sorry for you." Dumbledore sighed, shaking his head. "In sixth year and Voldemort assigned you to kill me."
The look on Draco's face was horrified. "You… you know?"
"Yes. You having the Dark Mark is also something that I feel sorry for."
"You're a Death Eater?" Hermione gasped.
"But what do I get in return for this?" Draco asked.
"First, Slytherin will get 50 points for your bravery if all four of you come back. Second, I will let your father go free from Azkaban. Is that good enough?"
Draco looked at the floor. "You'd set my father free and give 50 points to Slytherin?" He asked.
When Dumbledore nodded, he added, "I want Slytherin to win the House Cup. And my father free. Otherwise, I'll tell Voldemort."
"Slytherin will win the Cup, and Azkaban will have one less prisoner. Agreed?" Dumbledore said.
"How do I know you will keep your word? Should we make an Unbreakable Vow?"
"Dumbledore does not need Unbreakable Vows to be trusted! The question is will you keep your word, Malfoy?" Harry was too busy looking at Draco that he did not notice Dumbledore was staring at the floor.
"I will, Potter. Know that much." Draco muttered, and then looked at the Horcruxes. "But what're those?"
"Voldemort's Horcruxes. Do you know what a Horcrux is?" Dumbledore asked.
Draco looked at Harry and could tell that he knew what it is from the look on his face. "No. What are they?"
"You-Know-Who has Horcruxes?" McGonagall exclaimed. Standing by the doorway, everybody else had forgotten she was there.
"Again, tell me what are Horcruxes!" Draco demanded.
McGonagall took a deep breath before she explained. "A Horcrux is an object where a wizard or witch, most often evil, puts a part of their soul into."
"How do they make one?" He asked.
"To make one, you have to kill somebody. If you were to make one, but want to take what you did back, it was cause great pain, and very well might kill you. You-Know-Who made five Horcruxes."
"Seven." Dumbledore corrected. "I destroyed the rotting body of a rather ugly snake before you came in. The other one is Harry. This is why we must do this. He might die, but then Voldemort will become mortal. If this works, you will finish Voldemort off once and for all."
"What do we have to do?" Draco asked.
Dumbledore smiled. "It is quite simple, actually. First, we have a talk with Professor Slughorn…"
"What?" Horace Slughorn was confused. He had no idea why Ron Weasley would need this potion.
He had received a note just a minute ago by owl in the Potions classroom. Thankfully, there were no students in the room to witness this.
Dear Professor Slughorn,
My name is Ronald Weasley. I am in your Sixth-Year Potions class, and I would like you to help me with something. Actually, Dumbledore would also like you to help.
He wants you to brew a potion by the name of the Reverse. I think it is quite an odd name. Dumbledore thinks it will stop Voldemort, no, the Death Eaters, for the last time. This plan will involve Voldemort's death.
We know about the Horcruxes. Voldemort has seven. Please help us defeat him.
Your Student,
Ronald B. Weasley
Deciding what do was harder than it seemed for the Professor. He knew the effects of the potion quite well, and he did not know how it would stop him.
But Dumbledore wanted the potion. He would have to brew it. If it would stop him from raining terror, he would do it.