Sirius was bored again. After successfully rescuing Harry and his friends from the Ministry, going back to being trapped inside the Grimmauld Place seemed like torture. He was roaming the house as usual, when he saw it. A Pensieve was standing on the table, and it was filled with swirling liquid. He stared at it, wondering how it got there. The only thing he could think of was that someone had gotten in while he was at the Ministry, but he couldn't understand why would they simply leave this and not do anything more sinister. Then he notices the note next to the Pensieve. Sirius picked the note up and peered at it, and as he did, a picture fell down onto the floor.
Sirius,
I was forbidden from telling you, but recently I figured out a loophole. I wasn't forbidden from showing you. Look at these memories and you would understand. You would understand everything. You'll understand...
There was no signature, or any idenfitication, except for the picture. It was damp, like someone cried while holding it, allowing their tears to fall onto it. The picture showed all four Marauders, smiling at the camera. Sirius and James were in front, grinning exuberantly and giving the camera a thumbs-up. Remus stood slightly to the left, with a much more subdued, but still genuine, smile. And on the right...
Sirius' fists clenched themselves as he stared at Peter's smiling face. He looked at the note again, and saw that new lines had appeared.
The note has a tempus charm on it. I know you must abhor the very sight of me right now, but I beg you to view the memory anyway. All will be clear once you do. You'll understand, and you'll forgive me. I know the idea seems preposterous to you right now, but you'll think differently once you view the memory.
Sirius hesitated. He didn't want to, but his curiosity ate at him. Besides, there was no harm in this. Decision made, he dove into the memory. He found himself standing in Dumbledore's office. There was a boy with him, and Sirius recognized him easily. It was Peter.
"Please, sir, you cannot..." Peter says. "They are all I have..."
"I understand how you feel, which is why I will give you two a special mission," Dumbledore was saying. "And in exchange, I will keep what happened last night a secret."
"But what if they...what if they hate me...?"
"That is, I am afraid, a price we all must pay," Dumbledore says. "I paid it too. Just ask Aberforth. We all must pay a price for the sake of the innocent."
"Who have you lost, sir?" Peter asks.
"Her name was Ariana, and she was my sister," Dumbledore murmurs. "No one except me and my brother, and now you, knows about her, and I'd prefer it if that too remains between us."
"I will tell no one, sir." Peter says.
"Good. You must tell anyone what we talked about tonight," Dumbledore says seriously, giving Peter the intense look. "Now your task is to join Lord Voldemort, and gain his trust using any means necessary. We need someone on the inside if we are to have any chance of winning this war.
"But...I can't...I can't..." Peter was struggling to catch his breath. "I cannot betray them..."
"You won't be betraying them," Dumbledore says kindly. "You'll be saving them. I know you want their approval. You want them to see you as their equal. What better way to do it than save their lives?"
"I..." Peter faltered for a couple of seconds, before his expression turned to one of determination. "I will do it."
"Good," Dumbledore says. "And you must not tell your friends anything until I allow it."
Peter nodded, and that was when Sirius was ejected out of the memory. He sat there on the floor for a couple of minutes, and then his expression turned to one of shock. Shock and guilt.
He looked down at the note, and sure enough, the final portion of it was now revealed.
You are feeling guilty right now. I can tell. You were never someone who hid their emotions well, so it's easy to guess what you are feeling for someone who knows you like I do. And...was I right, Sirius? Do you forgive me now?"
Whether you do or not, I will always be a Marauder at Heart. A Marauder...and your friend.
Wormtail
A couple of tears fell onto the note Sirius was holding.
P.S: If you do forgive me, meet me at the Shrieking Shack on October 31st. Bring Moony along. It is on a Halloween night that barriers between life and death are the weakest, and I reckon that it's time for Marauders' reunion.
"I forgive you, Petey," Sirius whispers. "And I'll be there. We'll be there."