Sirius is freed from Azkaban and finds out you have a baby. At first he thinks you moved on, but it's more complicated than that. The baby is Harry, and you kidnapped him.

You know kidnapping is wrong, but Dumbledore didn't give you a choice. Harry is your godson. He should have been sent to live with you, not the Dursleys. When you discover they've been abusing him, you know you can't leave him there.

After a little arson, a faked pregnancy, and a de-aging potion, Harry James Potter is declared dead and becomes Harry Sirius Black.

But now Sirius is back and you have to figure out how to become a family after everything that happened.