Sera lives in a world where souls are only complete when joined with their destined other half. At 18-year-old Sera has always felt incomplete, like a missing piece of herself was lost. When her soul mark mysteriously glows near an ancient mirror, she discovers her other half is trapped inside: Zane, a vampire king from centuries past, sealed away by betrayal. As Sera digs deeper into his dark history with the help of her aunt and a modern vampire ally, she must decide if freeing him will heal her-or destroy her.