A/N Don't own

Harry returned from his talk with Remus just after midnight. He had used his cloak of invisibility to escape the punishment that would come with defying curfew. They had made small talk and avoided the major subjects. Remus refused to tell him about the order, claiming that Dumbledore was right, not telling him was safer for everyone. Frustrated, he had left the room, leaving Remus staring at the doorway.

Harry had noticed something however. He was keeping Sirius up to date with the happenings he was aware of. Mostly, the letters were long rants about Umbridge. Sirius and he had been writing back and forth more often. His Godfather had a house now, he didn't have to be on the run all the time.

Remus didn't know anything. Padfoot was keeping Moony in the dark and the Boy-Who-Lived didn't know why. According to the stories about his parents and the Marauders, the two were best friends. Well, his dad and Sirius had been, but James Potter had given his life for his wife and child. Harry assumed that the two would talk things through and become best friends.

He wrote Sirius a letter, avoiding the subject and asking him to meet him in the cave next Hogsmeade weekend. This was dangerous, yes, but Harry knew that it was worth the risk. The Black was careful, a trait that he acquired in Azkaban, the Wizarding prison.

It was during breakfast that he got his answer. This weekend. He was excited. This mystery had been bothering him all week.

Harry told his friends that he had an appointment and they understood. Actually, Hermione understood and dragged Ron into a shop, softly explaining what Harry meant. Harry laughed at their antics and walked towards the cave.

The climb was just as exhausting as it had been the last time. He was panting when the cave appeared in his eyesight. He entered the cave and saw the ex-convict standing in the middle of the cave.

Sirius spotted him almost immediately and spread his arms wide open in invitation. James' son hugged him and stepped back to look at his godfather. He looked healthy, but his eyes betrayed the darker secrets that were hidden from the world. Sirius Black had many secrets, Harry intended to unravel at least one of them.

"It's good to see you Sirius," he said.

"Good to see you to, Harry," Sirius replied.

"What's urgent?" The last male that carried the Black name conjured two chairs and sat down, gesturing to Harry to do the same.

"I spoke to Moony last night. He didn't know anything about the things that I told you."

"You told me not to," Sirius lied.

"I told you specifically which things were the secrets, Padfoot. I assumed that you would tell Remus everything. He is your best friend after all," Harry pried.

"He isn't," Sirius grimaced as he said this.

Harry was extremely confused, why weren't they? What happened? Hearing his own words he realised that he had spoken aloud.

"Remus and I have been fighting for a long time. Ever since October, actually. October 1981. The 13th of October 1981," Sirius still knew the date, even after all those years.

"Marlene McKinnon was a member of the Order. She was beautiful and killed somewhere July 1981. Her whole family, she included, were murdered by Death Eaters. Her sister, Amanda, was the only McKinnon that survived. She went to the Order, not for protection, but revenge."

"Your parents were busy with each other, you, the Order and their work. I barely saw them these days. Remus was convincing the werewolves and that left me. Amanda and I hung out all the time. We ate together, we lived in one house, we fought together, we did everything together."

"Instead of falling in love with each other, we became siblings. According to Lily we were flirting and a little bit too affectionate, but we were just having fun. That was around the time when Remus gave up on the werewolves and came home."

"It didn't take long before they fell in love. Remus told his secret and she was fine with it. She even promised that she would become an animagus as soon as the war was over." Sirius couldn't help but laugh.

"It was the 13th of October that Remus decided that he would try again. There was a trio of werewolves that had been spotted near my apartment. Remus would transform at my place and James would guide him to the trio. That's where everything went wrong."

"Amanda came by to discuss a potential suspect that she'd been tailing. She saw Remus howl at the moon from a distance, she was scared. I took her to the couch and we talked about it, she seemed alright. I let her go home and everything went back to normal. I didn't know at the time that Remus found out anyway, the fighting started that day."

"We didn't tell anyone that she saw him and there was only good news for a while. Remus convinced the werewolves and we had a small victory party after we won the battle in Diagon Alley."

"Remus has this thing, a werewolf treat. When he's extremely happy or angry his eyes turn yellow. When he asked Amanda to marry him on the 30th of October and she said yes, his eyes flashed. They were interrupted by a floo call, a man begging for help."

"They gave it to him of course. Remus got wounded and had to stay the night with his healer. Amanda came to me, afraid and scared. She told me what happened. She was upset. She went to me for comfort and cheated on Remus with me."

"She was engaged and I didn't even think, I just did it. Remus was released far earlier than we thought. He went to my house when he couldn't find Amanda and saw us in my bed, sleeping. He woke us up and yelled at me. He told us that he hated us and left."

"Amanda went out before I could stop her, she left too. I went to Peter and got suspicious when his house was covered in dust, I went to Godric's Hollow immediately and found out that your parents were dead. You lived though, I promised myself that I would take revenge and left you with Hagrid. Peter could lie, but he wasn't very good with fights. I went to Amanda for help, we'd take revenge together."

"She was dead Harry, she was ambushed at her place and killed minutes after she left me. In my rage I tracked Peter down, I blamed everything on him. The Marauders died that night. Moony, Wormtail, Padfoot, and Prongs no longer exist. The friendship and the trust, the love and the adventures, the boys looking forward to fighting a war died. Remus, Peter and me are just three projects of the war. We are men, friends no more."

"I made a mistake, there's no turning back."