Waiting for a White Tomorrow

Twin!grey!Slytherin!Harry AU: Penelope Potter is abused even moreso than her brother thanks to her resemblance to Lily. One day, it gets to be too much and she runs away, making her way to Gringotts and finding a list of Potter properties. She lives alone for almost a year before going back for her brother. / Slytherin cast, Dumbledore bashing, future slash, full summary inside.