Only two people gets in contact with him, his maid and his girl-friend (Grace Kelly). Grace wants him to marry her, but James is doubtful because he is from a different background and class.
James is bound to his room. So he keeps looking around through his window on other apartments. James now tracks other peoples personal lives closely through his camera, by their windows. On his list there is a newly wed couple always in a romantic feel, another women who entertains other men in her apartment, another couple who love their pet dog, and there is one women who rehearses for her dinner with her friend, and the couple who have nothing interesting to watch, but in the due course becomes the part of the main screenplay. When James suspect that the husband has killed his wife, for which he tries to investigate with the help of his maid and his girlfriend. And with all twists and turns there is a happy ending.
This movie is a true master piece of Alfred Hitchcock.