After a series of unfortunate events, Rosemary and Guy Woodhouse move to Paris and find comfort in their new neighbors, the Castevets. This wealthy, successful elderly couple takes charge of the newcomers and becomes deeply involved in the lives of the Woodhouses. They seem to be doing well when Rosemary becomes pregnant and Guy's career takes off. Later, plagued by fear and illness, Rosemary becomes increasingly distrustful of her husband and their neighbors, suspecting that they have wrong plans for her unborn child.