Loki meets a woman who can give him the two things he's always wanted: a throne and an army. And if he must marry a startlingly beautiful woman in the balance so be it. She hands him Asgard on a plate, and has an unexpected effect on him.
A blast from Remus' past shows up and she's a handful. Although most of what she does is just giving Remus the pushes he needs. Follows cannon.
Starting after the final battle. Suppose the Lupins had survived, but Greyback's pack forces the passing of legislation that puts Remus into Azkaban.
Harry decided to let Teddy borrow the resurrection stone on his graduation from Hogwarts to visit his parents.