Journalist Grace witnesses a murder in the neighboring apartment of two twin sisters. However, when the police find no evidence of the crime, Grace takes things into her own hands. With the help of a private detective, she soon discovers more about the sisters’ relationship than she bargained for.

Billed at its time as “the most frightening film since Psycho,” this ‘70s homage to all things Hitchcock by his biggest fan Brian De Palma, overflows with slasher artifice, split screen bravura and glorious plot twists. Bernard Herrmann’s score is chilling, and the descent into madness irresistible.