Harry stared at Snape, eyes wide, and then slowly nodded. He knew it would be better to have Snape help him, not Sirius or Lupin.

“Good,” said Snape shortly. “I trust you would not mind leaving this house?”

Harry shook his head. Snape pulled a scroll of parchment from his pocket and set it on the table, then pulled out his wand. Harry flinched, but remembered that Snape wasn't going to hurt him.

“Pack,” said Snape and the few belongings that he'd removed from his trunk flew back inside. Snape tapped Harry's trunk with his wand and it vanished instantly. Snape moved over to where Harry sat on his bed and picked him up with no hesitation.

“Hold tight,” advised Snape.

Harry clenched his fists in Snape's robes as he felt the uncomfortable sensations of Apparition.

He was still recovering from the Apparition when he felt Snape putting him down. He opened his eyes and found a slightly grubby room. The bed he was on was comfortable, though.

“It's a bit dirty, but it shall suffice,” said Snape, glancing about the room. “This will be your room. When you are ready to, I will show you the rest of the house.”

Snape left him alone in the room and after a few minutes, Harry gingerly climbed out of bed. His trunk was at the foot of the bed. Several curtainless windows allowed gleaming sunlight to pour into the room. A desk and chair were against one wall, and a wardrobe opposite.

Harry limped over to the window and saw that the house was surrounded by trees. The grass around the house didn't look as thought it had been tended to for years.

He soon grew bored of the room and wandered out. He headed down a short hallway and towards the only open doorway. He found a kitchen and dining room within it, and Snape rummaging through the cupboards.

“I see you've found your way out of your room,” said Snape without turning around.

“Yeah,” said Harry, realizing that Snape had spoken with no malice, merely stating a fact.

“Go ahead and sit down. This is your home now, too,” said Snape.

Suddenly, it all clicked into place. Harry stumbled backwards, his eyes wide.

“You--you killed Dumbledore,” he gasped.

“Thank you for stating the obvious,” said Snape, turning to face Harry.

“No, no, no,” stammered Harry, unable to put his thoughts into words.

Snape had killed Dumbledore to save Harry. He had been trying to help him all along.

Snape approached him cautiously, as though he thought Harry was going to attack him.

“Potter, come sit down and I'll explain,” said Snape.

He reached out a hand to lead Harry over to the table, but Harry flinched. Snape backed up and gestured to a chair.

“If you want to know what happened last year, you're going to have to sit down,” said Snape.

Harry hesitated a moment, then moved to sit on the chair. Snape returned to the cupboards and picked out two cups and tapped a teapot with his wand. He poured them each a cup of tea and pushed one towards Harry.

Snape raised his cup and took a sip before looking intently to Harry.

“It started one year ago, after the fiasco at the Ministry. Dumbledore came to me with a plan. No, actually, this plan had been forged for many years. He knew about the Horcruxes since I came back to Hogwarts sixteen years ago. For the past two years, I've been following Dumbledore's instructions and assisting him with finding a destroying the Horcruxes. And last summer, when he located the Gaunt ring, he tried to expel the Horcrux, and in doing so, released a curse that would slowly kill him.

“Also, I entered into an Unbreakable Vow with Narcissa Malfoy, who wanted me to help Draco with his mission. What that mission was, I had no idea at the time. When I learned of the mission, my job as a spy became much harder. On one hand, I had Draco Malfoy to control, and on the other hand, I had Dumbledore controlling me.

“Yes, I do mean controlling me. You see, when I returned to the castle so long ago, I agreed to do anything, anything to be back in Dumbledore's favor, and to get his trust back. He and I agreed upon an Unbreakable Vow, one that would force me to obey Dumbledore's command.”

“That's the reason he trusted you?” gasped Harry. He'd had no idea Dumbledore would outright force Snape to be trustworthy to him.

“Yes, Potter, your precious Headmaster would do something like that. He was nothing like the part he played for the students. He lied, he manipulated. Of course, you knew about the manipulation, though I'm sure you didn't realize it at the time. Both you and I were slowly trained to the Headmaster's will, and when he finally asked--no--pleaded with me to end it, I had to. And I did it with the most hatred and loathing in my heart, because I knew that was exactly how he'd planned it to be. Everything had been done his way. Always. And even in death he is making me do his will. And that is why you're here now.”

Harry was stunned at Snape's declaration. Yes, Dumbledore had been manipulative. He'd known that. But to force Snape to kill him? Wouldn't that make him just as bad as…

“The Dark Lord, yes,” said Snape. “Only Dumbledore's men did it willingly, albeit not knowing about the lies he told to ally them to his side.”

“Yeah, I started to figure that out last year, after he finally told me the truth about Sirius and the prophecy,” said Harry.

“And now we get to Dumbledore's last request,” said Snape.

“I thought that was for you to kill him,” said Harry.

“Yes, but he had one other request,” said Snape. “The one that ultimately, is much more important than his death.”

“What was it?” asked Harry.

“He wanted me to help you defeat the Dark Lord. I am to train you and teach you all I know about Defense,” said Snape. “I was reluctant to do so on the Tower, but I can see now that you're going to need all the help you can get.”

“I know,” said Harry. “It just seems like it will never be enough, that I won't be strong enough to stop him.”

“You have the power, it's just a matter of training you to use it, rather than idiotic little charms and jinxes. I can teach you hexes, curses, even the Dark Arts.”