Popular radio show host Dave Garver (Clint Eastwood) becomes restless in his relationship with his girlfriend (Donna Mills). Impulsively, he goes out and sleeps with a woman (Jessica Walter) he meets at a nightclub. After the fact, he finds out she was not an anonymous hookup, but an obsessive fan who has called in repeatedly to request he play the song "Misty." Garver soon discovers extricating himself from the woman will be no easy feat as she becomes increasingly psychotic.