22 year old Piper Grey is the child prodigy younger sister of Meredith Grey, the youngest daughter of Thatcher and Ellis Grey. Or in which 38 year old Mark Sloan comes to Seattle Grace to win Addison Montgomery-Shepherd heart back, but that all changes when Mark Sloan mets Piper Grey and falls deeply in love with her. Book 1 Mark Sloan x oc Grey's Anatomy season 2-6