Archie Landrum is a brilliant mathematician who is hired to work on a New Mexico farm owned by a reclusive widow, Katherine Samuels. The two quickly develop a close friendship and peaceful existence which is shattered when Katherine's daughter Lucy, a popular TV star, returns home to visit. Lucy and Katherine's relationship has become strained and combative over the years due to the mixed feelings of anger and jealousy they each harbor. Archie is immediately stricken with passion for Lucy and begins to pursue her relentlessly, despite Lucy's constant rebuffs. The repeated rejection causes Archie to grow increasingly delusional, and soon he cannot separate Lucy's private life from the characters she portrays on TV. Meanwhile, Lucy and Katherine gradually begin to confront their past. When Katherine tells Archie she and Lucy need to be alone and that he must leave, he becomes irrational. Desperate and completely overtaken by his obsession with Lucy, Archie concludes his only option is to kill her.