Billie, a teenager with a troubled past, moves to a new town with her mother, seeking a fresh start. However, their arrival coincides with a gruesome murder, which sparks a series of eerie events and mysterious encounters.
As Billie navigates her new school and relationships, she's drawn to Jasher, an introverted and enigmatic classmate with a fascination for true crime and psychopathic behavior. Unbeknownst to Billie, Jasher harbors a dark secret: his ability to switch personalities, adopting the persona of "Echo," a menacing and calculating alter ego.
As the body count rises, Billie finds herself at the center of a sinister game, with Jasher/Echo's true intentions unclear. With her own dark past and Jasher's duplicity, Billie must confront her fears and unravel the tangled threads of the murder mystery before she becomes the next victim.
