Thanks for all the hits, everyone. It was such a cute story, I wish I could remember who wrote it. Sirius rescues harry from Godric's Hollow, home schools him, and they rescue Hermione off the Hogwarts' Express (due to Luna's vision of her becoming Harry's senior wife) prior to her first year there.
Sirius awakens in the night, tells his wife something has happened to Lily & James. Harry has multiple wives (Luna, Susan, Daphne) Hermione is injured & rescued from the Hogwarts Express. multiple chapters