Jim Holman, 29, is an engineer going through a difficult divorce. One night, after leaving his wife’s lawyer’s office, he decides to have a drink at a Brooklyn jazz club. There, he becomes mesmerized by a 22-year-old singer named Helene Raymond. He manages to convince her to let him drive her home. On the way, she shows him needle marks on her thigh and tells him that she is a junkie, and warns him that she will end up hurting him because she is no good. She says she has been sober for three months but she fears she will relapse. He says he doesn’t care, because he is already in love.

Their relationship is sabotaged by the band leader, who is Helene's ex-boyfriend. He is possessive, and manages to persuade Helene to go back to heroine. Holman tries to help her quit by taking her to the Adriondacks. He says he will marry her, and she moves into his apartment with him. But when her ex-boyfriend tracks her down and gets her hooked again, Holman loses his temper and murders him with his own saxophone.