Rosemary (Mia Farrow) and Guy Woodhouse (John Cassavetes) are newlyweds, but Rosemary has no idea that her wedded bliss is about to come to a horrific end. Her husband's ambition as a struggling actor is about to plunge her into an abyss of terror like she has never known. In exchange for a taste of fame, Guy makes a deal with the devil that puts his wife and soul in jeopardy. When Rosemary becomes pregnant, her husband becomes odd, her neighbours (Sidney Blackmer and Ruth Gordon) border on obsessive, and her normal life turns into a surreal nightmare. Slowly, she begins to realise that a seed of evil has been planted... and she is its host.