Photographer Jeffries (James Stewart) broke his left leg while standing in the middle of the race track, and had to recuperate at home for seven weeks. In addition to the insurance company's nurse Stella (Sylma Ritter) and girlfriend Lisa Carroll Fremont (Grace Kelly) who come to take care of them every day, the bored Jeffries can only pass the time by watching the neighbors' daily lives in front of the window. On the second floor of the apartment opposite live costume jewelry salesman Lars Thorwald (Raymond Burr) and his wife Anna (Erin Winston), and the couple quarrel constantly. One rainy night, Jeffries saw Lars go out several times with a suitcase. The next day, Jeffries saw Lars wrapping a saw and a knife wrapped in newspapers. Jeffries became suspicious, suspecting that Lars had killed Anna and dismembered her. However, Jeffries did not witness the incident and did not see the body. So what's the truth? Was Jeffries's speculation just his imagination? How did Jeffries find evidence to confirm his suspicions?