Guilt.

Elizabeth comes home from college to stay with her parents. She begins having violent dreams where she sees a darker version of herself killing people close to her. Then those same people show up dead in real life under mysterious circumstances. Elizabeth was diagnosed with schizophrenia when she was 12 after an accident occurred that killed her younger sister. Now, Elizabeth doesn't believe she's sick, she believes she's haunted. Is she right and whatever is haunting her is killing people close to her? Or is her illness gotten worse and turned her into a murderer?