Successful magazine photographer L.B. Jefferies - Jeff to his friends - is on week seven of eight of a cast on his broken leg sustained while on assignment, the problems being not only not able to work, but being confined to his Greenwich Village apartment over the course, now during a heatwave, with his only visitors being Stella, the acerbic-tongued insurance provided nurse, and socialite Lisa Fremont, a fashion reporter and his girlfriend. While he is aware that Lisa sees their relationship as *the* long term, Jeff is thinking about ending things with her in not seeing her following him around the globe in often less than comfortable situations while on assignment. With his apartment facing onto a courtyard surrounded by other apartment buildings, Jeff largely relieves his boredom by spying on his neighbors who have their windows wide open due to the heatwave, many whose stories, which he can only surmise by what he sees, are of a personal relationship nature: the lonely woman who tries to make her life less lonely, the dancer with many suitors who probably don't care about her beyond her sex appeal, a middle aged couple who owns the neighborhood dog lowered down to the courtyard garden on a pulley system, and a man, seemingly a salesman, caring for his bedridden female companion, probably his wife, they all often serenaded by a songwriter on a piano as he works. While they are both disgusted by his voyeuristic activities for different reasons, Jeff is able to convince both Stella and Lisa that, based solely on his behavior, that the salesman most likely murdered his wife by mutilation, seemingly for another woman. While he also tells his fellow war veteran friend, now Police Detective Tom Doyle, off the record, Tom, while indulging him to an extent, is only humoring him in believing his imagination going into overdrive in his boredom. Left to their own devices, Jeff, Lisa and Stella enter into a game of cat and mouse with the salesman to discover evidence, the salesman who they learn is named Lars Thorwald, that game which may become deadly if what they believe is indeed true and Thorwald feels like he is being cornered.