Dear Remus,
They gave me a quill and a piece of parchment to write a note to my loved ones, for when I die. It sounds nice, but it's cruel, in a way. It just serves as a reminder that I'm going to die, and no one will care.
You hate me. I know you do. But the thing is, you're the only person left who ever loved me. If you're still alive.
But you have to be. I need to believe you are alive, because I can't bear the thought of you being dead. Even writing it down makes me want to throw up. If you died because of the aftermath of that horrible night, that would mean I am responsible for all of my friends' deaths.
Because I am responsible for James and Lily's deaths. I did not kill the thirteen other people, but I won't try to convince you of that, because you wouldn't believe me anyway and besides, I would run out of parchment.
I'm getting worse every day. I can see my reflection in the bottom of the bowl of food they give us every day. I look like a corpse. I might be one myself in a few weeks.
I don't think I can keep fighting for much longer. The dementors suck every bit of happiness out of me – not that there was much left anyway. My days consist of repeating my worst memories in my head. I barely sleep, and if I do, I have nightmares and wake up even more tired the next day. I relive my arrival at James and Lily's destroyed house, carrying little Harry with that cut in his head and having to give him to Hagrid, the full moons before we could help you, the moment I found out Regulus had died, my arrival here, that street after Peter blew it up and disappeared, my fights with my parents. I hate that even they have a spot in the cursed place that is my memory, that apparently I still care about everything that happened in that house, that I care so much that I have to relive it daily.
The only thing keeping me up is the knowledge that I am innocent. I know you won't believe me, and I know that even if you do, this letter will only reach you after I am dead, so it'll be too late for me anyway.
In the beginning, I focussed on happy memories, like Harry's smile, your smile, James's smile. But the dementors feel it when I am happy, and they come to my cell to suck that happiness out of me. Even now, I feel them coming. I feel the cold and the despair pulling on me, begging me to break and fall apart. But I refuse to. The two of us are the only Marauders still standing, and I can't die on you and Harry, even though I will never see you again. But I refuse to give up. I'm not one to give up easily, Remus, you know that.
It's never quiet here, there's always someone screaming or yelling, even at night. Most of them are really young, too, about our age. The other day this kid was brought in, Crouch is his name, I think. He was in Regulus's year at Hogwarts. I almost didn't recognize him. He was pale as a ghost and already screaming, two minutes after setting foot inside this cursed building. The dementors have that effect. It almost makes me happy Regulus died – if he had been captured and brought here, I don't think he would have survived for long. He was a good kid, nothing like the people here.
Speaking of my amazing family – my dear cousin Bellatrix is here, too, which isn't surprising. It's only surprising she let herself get captured. She was brought in together with young Crouch. They are placed a few cells away from me, so they must've done something bad. I keep wondering what it is. Did they kill someone? Who? If any of our other friends have died... If it's my fault, somehow... Well, I can't hate myself more than I already do.
Be careful out there, Moony. Please make new friends, people who can protect you like I have attempted to do. I'm sorry you are alone now. It's all my fault. I convinced Lily and James to switch secret keepers last minute, to make Peter secret keeper instead of me, and tell everyone it was me. The Death Eaters would go after me and the Potters would be safe... Well, that was my plan. Little did I know Peter was the spy. I should've told you, should've trusted you. This is all my fault. I let you down, and now we're the only Marauders left, and soon I'll be dead too. I'm sorry.
Love, Sirius