In retrospect, Sirius should have planned his confession better. He knew not to confess during the middle of a prank, really, he did. Especially this prank. After all, how effective was a love declaration when he literally could not say the words "Remus, I love you"?

Remus Lupin finds the Marauder's Map again and does his best not to let a certain ghost from his past haunt him.

Soulmate AU: Shortly after his fifth birthday, Sirius Black's soulmate stops all communication with him, and he concludes that something terrible must have happened to his soulmate. Just before his fifth birthday, Remus Lupin is bitten by a werewolf and changed into a monster. And he knows monsters don't get to have soulmates.

Sybill drinks tea and tells the future.

Mrs. Figg receives an owl from none other than Dumbledore asking for a favor.

"Remuusssss. We need to have sex. Like right now. For seven years." When Dumbledore promised him safety should he decide to come to Hogwarts for his education, Remus didn't think he took Sirius Black into account.

The exact moment James Potter falls in love with Lily Evans. Or alternatively, Remus John Lupin is a bastard and is not to be trusted.