Brandon Shaw (John Dall) and Phillip Morgan (Farley Granger) believe in a philosophy of intellectual superiority that should allow them as superiors to decide if those who are inferior should live or die. They consider their former classmate David Kentley (Dick Hogan) inferior. To prove their point they decide to strangle David with a rope and place his body in a chest. Then, to flaunt their superiority and certainty they won't be caught, they throw a dinner party to begin right after their murder. The trunk they have hidden David's body in becomes the table they serve their party food upon. They invite everyone who is important to David including their former teacher Rupert Cadell (James Stewart). During the course of the party, they challenge Rupert on the philosophy of intellectual superiority while dropping hints about David's murder. The guests wonder why David hasn't arrived at the party. Their confidence that they have gotten away with the perfect crime becomes shaken when they see the rope they used as a murder weapon sticking out of the trunk.