Mrs. Violet Venable (Katharine Hepburn), a wealthy and powerful New Orleans widow, approaches a psychiatrist, Dr. Cukrowicz (Montgomery Clift), with an offer to make a large donation to his clinic. In exchange, she wants him to perform a lobotomy on her niece, Catherine Holly (Elizabeth Taylor). Catherine has been suffering from emotional problems ever since she returned from a European vacation with Mrs. Venable's son, Sebastian, during which Sebastian died mysteriously. Mrs. Venable insists that Sebastian was a kind and sensitive poet, but Catherine seems to know more about his character and habits than his own mother does. Dr. Cukrowicz suspects Mrs. Venable of ulterior motives and begins treating Catherine with psychoanalysis despite the old woman's objections. During his treatment he learns the terrible truth about the real cause of Sebastian's death.