Norah Dain, [Juliet Prowse](/ actor/juliet-prowse), a nightclub disc jockey and aspiring actress living alone in a Manhattan apartment, begins receiving a series of obscene phone calls from someone who seems to be watching her daily. She also discovers a decapitated teddy bear left in her apartment.
Lt. Dave Madden, Jan Murray, a police detective whose wife was raped and murdered, takes a personal interest in Norah's case. He behaves in ways that raise questions about his motives—he suggests he might be the caller, secretly records his conversations with Norah, listens to tapes of Norah and other women discussing obscene calls, and immerses himself in pornography and perverse behavior while his own ten-year-old daughter is exposed to such material, drawing complaints from his superiors.
The obscene caller is seen to be Lawrence Sherman, Sal Mineo, a waiter at the nightclub where Norah works. Lawrence lives with and cares for his 19-year-old sister Edie, Margot Bennett, who is brain damaged with the mind of a child. His guilt over a past accident—when Edie, as a little girl, witnessed him with an older woman and fell down the stairs—keeps him from forming normal romantic relationships. He is also frustrated when Edie dresses up in adult clothes and makes advances toward him. He tries to relieve his frustration by visiting adult bookstores and movies in Times Square, yet remains fixated on Norah.
Despite Lt. Madden's warnings that the caller could be someone Norah knows, she does not suspect Lawrence until it is nearly too late. She remains friendly toward him and even appears attracted to him, complimenting him on his body when they meet at the gym, and offering to stay late after work to teach him to dance.
Marian Freeman, the older, experienced manager of the nightclub where Norah and Lawrence perform, Elaine Stritch takes a personal interest in Norah and tries to protect her. She offers to stay overnight with Norah at her apartment, but Norah senses Marian is making a lesbian pass and asks her to leave. Marian departs in a huff, still wearing Norah's coat. Outside, Lawrence sees Marian leave and, mistaking her for Norah, chases after her and kills her.
After closing time, Lawrence assaults Norah in the empty club, raping her but not killing her. Lt. Madden, who has by now deduced that Lawrence was watching Norah via a mirror reflection, arrives too late to stop the rape. He beats Lawrence and then, for reasons not explained, lets him go. Lawrence runs through traffic in Times Square, imagining he is running through Central Park toward a welcoming Norah. Police eventually gun him down as the film ends.
