Rosemary and Guy Woodhouse move into an apartment in a building with a bad reputation. They discover that their neighbors 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: Rosemary meets a woman in the washroom that dies a mysterious death; Rosemary has strange dreams and hears strange noises. Then Rosemary falls pregnant and begins to suspect that her neighbors have special plans for her child.