Rosemary Woodhouse (Mia Farrow) and her husband Guy Woodhouse (John Cassavetes) move into a new apartment building. Guy becomes immediately drawn to the weird, older neighbors, Minnie Castevet (Ruth Gordon) and Roman Castevet (Sidney Blackmer). Rosemary remains apprehensive of them. One night Rosemary dreams that she is raped by a horrible beast. A few weeks later, she finds she is pregnant. As her pregnancy progresses, ominous events begin to surround Rosemary. She starts seeing terrible signs, such as odd behavior and mysterious deaths, everywhere that there is something wrong. Now she has to find out the dark secret of her baby before it is too late.