Hermione was surprised to hear that. "Accio Snape's wand," she said, but nothing happened.
"You can not call something which no longer exists to you, Miss Granger," Snape told her from his prone position on her floor.
She took a moment to really look at him. She'd looked at his face, of course, to be certain it was him, but now she had the time and power to see the changes nearly a decade had wrought. Severus Snape looked better than she ever remembered seeing him look. While still thin, he wasn't sickly-looking anymore. He'd gained a little much-needed weight and his skin no longer had the look of a corpse. His hair reached nearly to his waist and was pulled back in a pony tail. He was wearing Muggle blue jeans and a black t-shirt emblazoned with "Irish dancers do it step by step!"
He made no attempt to move, silently watching her.
"You're supposed to be dead!" she blurted.
"A memory-charm is an easy thing to cast on a battle field. No one lied for me. They believed they saw me obliterated."
"And you just disappeared? You deserved to die for what you did!"
"That is true. Are you to be my executioner, Miss Granger?"
"No. I believe even you, Snape, deserve a trial."
At that, Snape hung his head. "Couldn't you just kill me and get it over with? Why put everyone through the farce a trial would be?"
"Shut up! I am not going to kill you. I've killed one man and that is enough."
"So, you know what it is like, then. The constant self-recrimination, the heavy weight of the knowledge that you took someone's life."
"I killed to save a dear friend! Don't you dare compare you killing Albus Dumbledore to what I did in battle, you bastard. The two are completely different."
"Killing one person to save another happens to be exactly what I was doing, Miss Granger."
"Bullshit! We all trusted you! I trusted you, and you killed the Headmaster. Harry saw you!"
"I killed Albus Dumbledore to save Draco Malfoy. I do not deny it."
"Draco Malfoy was not worth saving. He took his father's place at Voldemort's right hand when his father was killed weeks before the final battle."
"Albus and I had hoped we could save him, if only we could show him what was right," Snape whispered.
Hermione began to laugh. It was an awful, malicious sound. Snape just stared at her.
"You actually believed you could save Draco Malfoy? Are we talking about the same person? I would've expected it of Dumbledore, but such naivete from you, Snape? That little bastard all but had "Death Eater to be" tattooed on his forehead! How could you believe you could reform him?"
"He was a child. A child I had watched grow up. I believed there was some good in him, something that we could use to make him understand what he was taught by his father was wrong. I had killed before. He was still innocent."
"Innocent? Draco Malfoy was born tainted. He was destined to be evil, brought up to be evil. Evil was nurtured in him and anything that had been good was crushed out long before you tried to 'save' him."
"Believe what you will, Miss Granger. You always have. Albus was already dying from destroying the Horcrux. I had been the one brewing the potions that were staving off the end so that he could continue the fight, but they weren't working. He was beginning to die slowly, and he was in great pain. Avada Kedavra is quick, and as close to painless as a curse can be."
Snape stood up from where he had been lying on the floor. Hermione backed a few steps away, keeping her wand trained on him.
"Dumbledore was dying?" asked Hermione.
"Yes, of course he was dying. He was very old, even for a wizard, and the curse activated when he destroyed the Horcrux would have killed him in a matter of days without intervention. The potions I made were all that kept him alive as long as he did live, even if I could not take away the pain of his flesh dying. Surely, either you saw his hand or Potter told you of it? It wasn't the only part of his body that was that way, only the most visible part."
Hermione dropped onto the low couch. It was all so much to take in. Could she trust that Snape was telling the truth? If he was, did that not make what he did a mercy rather than murder?
"If this is all true, why did you disappear?" she demanded.
"What proof did I have? Who would take my word? If they didn't kill me on sight, they still would not have believed a Potions Master, even under the influence of Veritaserum. The only other person who knew he was dying was Minerva, and she was killed in the first wave of attacks. So, I went to Voldemort and made excuses as to why I had carried out the task he had set Draco, and covertly sent messages when I could. At the end, the final confrontation, I waited until I was certain Potter would win, cast a few memory charms, and left. My purpose was finished, no one would have believed me, and I had nothing left in that world. I snapped my wand and left."
"But, it was you? You sent those messages?"
"Of course, I did. Who else would have known where to send them? Who else would have had access to the information, and the impetus to give it to you?"
"We always wondered. Some of the other Order members, when Harry wasn't around, they speculated that it was you, that there was more going on than we knew."
Snape sighed, looking very tired. "The honest truth, Miss Granger, is that I am unwanted in the wizarding world. I spent years on tenterhooks, pulled one way then another, the consummate spy, ever watchful, never letting anything slip. When the end came, I saw a way out. Gods help me, I took it."