Famed playwright Sidney Bruhl debuts the latest in a series of Broadway theatre flops and returns to his opulent Long Island home and his wife Myra. Although their financial situation is not dire, Sidney is starving for a hit. He receives a manuscript of a play called ''Deathtrap'', written by one of his students, Clifford Anderson, that he considers to be near-perfection. Clifford recently attended one of Sidney's writing workshops and is now asking for input on his play. Sidney tells Myra that the best idea he has had lately is to murder Clifford and produce the play as his own. Myra realizes that's he's not just talking idly.