Making a habit of peeping in on others, Monsieur Hire witnesses a murder. With a real desire for the women involved however , he keeps quiet. He continues to watch her day after day, and eventually he is discovered by her. She doesn't shy away, instead she forms a relationship with him. Obsessed with this young woman, he does all he can to hold on to her. Knowing that she is an accomplice in a murder case which the police are working hard to crack, he pays the ultimate price to protect her.