Late one night, an emotionally disturbed woman, Abigail Macy, witnesses a murder. She reports what she saw to the police, but out of fear the killer will return to eliminate her as a witness, she keeps quiet about his identity. When the police investigate her claim, they find no evidence of a crime and, influenced by her psychiatrist's diagnosis that she was delusional, they close the case.
Abigail's condition deteriorates, and she shuts herself...