ACT ONE, SCENE ONE
The play begins with accomplished writer Sidney Bruhl finding himself having trouble writing the next big play. After his last few productions flop in the box office, he becomes desperate. He then reads a play by young writer Clifford Anderson and decides to steal it and kill him.
Clifford stops by Sidney’s office to get his opinion on the play, and while he being asked questions that allude to murder, he is killed as Sidney’s wife, Myra, looks on in horror. Sidney then wraps Clifford in a rug and immediately ignores what he has done by babbling on about how he plans to take credit for the play.
While returning after ridding himself of Clifford’s body, psychic Helga ten Dorp drops by to tell them that she is receiving bad vibes from the house. Helga wanders around the house revealing trivial information while missing the important facts. After she leaves, Sidney becomes elated at the fact that Helga had not discovered the murder. As he goes to turn off the lights he is snatched by Clifford, who is covered in mud. Clifford proceeds to attack Sidney as Helga predicted. Myra, in shock of the night’s events, collapses in an apparent heart attack. After Clifford confirms Myra’s death, he happily informs Sidney that the plan had worked. The apparent “murder” had all been an act to shock and kill Myra, so that they could be together.
ACT TWO, SCENE ONE
The second act opens with Clifford writing his manuscript, as Sidney sits with writer’s block even after two weeks have passed. Porter Milgrim, Sidney’s attorney, reveals to Sidney that he had seen Clifford locking his manuscript away and tells him to not fully put his trust in Clifford. Sidney decides to sneak and read the manuscript when he gets the chance and finds that Clifford is writing a play called Deathtrap, which reveals their whole plot for Myra’s murder. Sidney confronts Clifford only to be persuaded into believing that since the murder was so clever, they would never be caught.
Helga once again reveals to Sidney that she has a bad feeling about Clifford. After she leaves, Sidney calls Clifford over and tells him that he is ready to show the progression of act 2. Sidney asks Clifford to act out parts of the second act including violent struggle, then reveals the struggle was to enable him to have evidence to show why he needed to kill Clifford and that he plans to burn any remnants of Deathtrap. Sidney goes to shoot Clifford but the bullets in his gun have been replaced by blanks, then Clifford pulls out a gun with real bullets and handcuffs Sidney to a chair. Sidney escapes because the handcuffs are fake and then Sidney grabs and shoots Clifford with a crossbow. Sidney then grabs the phone to call the police, thinking that the fight is over. As Sidney calls, Clifford raises up behind him and pulls the arrow from his body and stabs him. In the end, both of them die.
The play ends with Helga and Porter wandering through the room as she reveals the events that led to their death. In a discussion of the play, both Helga and Porter realize that it would be a great thriller and begin to argue about who should claim the play as their own, while the curtains close.