Rosemary and Guy Woodhouse move into an apartment in a building with a bad reputation. They discover that their neighbours are a very friendly elderly couple named Roman and Minnie Castevet, and Guy begins to spend a lot of time with them. Strange things start to happen: a woman Rosemary meets in the washroom dies a mysterious death, Rosemary has strange dreams and hears strange noises and Guy becomes remote and distant. Then Rosemary falls pregnant and begins to suspect that her neighbours have...