Is the next 'Great American Play' worth killing for, or will the search be a Deathtrap...? Sidney Bruhl returns to his New England home from the latest in a long series of Broadway flops. He shares his pain of failure with his loving wife Myra. Sidney is afraid he doesn't have the touch anymore. While his wife's finances are still in good order, Sidney is hungry for another hit show. The very next morning, a manuscript arrives from a former student, Clifford Anderson. He had recently taken one of Sidney's writing classes and wanted Sidney's opinion on his completed play, Deathtrap. Sidney considers it to be near perfection. While Sidney ponders the possibility with Myra of killing for a new hit show, her weak heart convinces Sidney to take her advice and invite Clifford up to the house for suggestions and polish on his new play. Clifford arrives a few days later by train. Myra tries desperately over the course of an evening to convince Sidney to work with Clifford as equal partners, but to no avail; Sidney attacks Clifford, strangling him with a chain. Sidney disposes of the body, but still has to convince Myra to conspire with him.
She reveals nothing when they receive an unexpected visit from the psychic Helga Ten Dorp, a minor celebrity who is staying with the Bruhls' neighbors. But Helga senses pain and death in the house. Before she leaves, she warns Sidney about a man in boots who will attack him.
As they prepare for bed, Myra comes to terms with Sidney's deadly deed. All is calm until Clifford bursts through the bedroom window and beats Sidney with a log. Clifford then chases Myra through the house until her heart gives out. Myra collapses and dies with Clifford standing over her. Sidney calmly descends the stairs, uninjured, to Clifford's side. They exchange a few words about what to do with Myra's body, then exchange a passionate kiss.
Clifford moves in with Sidney as his assistant. The two work together at a partner's desk. Unfortunately, Sidney is still suffering from writer's block while Clifford is busily typing page after page of a new play. One kept suspiciously under lock and key. While Clifford is out grocery shopping, Sidney tries to break into the drawer, but fails. Once Clifford returns, he switches Clifford's manuscript with a fake. He is horrified to discover that Clifford is using the true story of Myra's murder as the basis of Deathtrap. He angrily confronts Clifford, who boasts about the play's potential. Sidney comes to realize from Clifford's behavior that he will not stop writing. Sidney lies about the solvency of Myra's estate as an excuse to assist Clifford while he contemplates a solution to Deathtrap.
A few days later, Helga stops by for candles in anticipation of a predicted thunderstorm. Immediately after meeting Clifford, she warns Sidney that Clifford is the man in boots. After she leaves, Sidney double-crosses Clifford. He asks Clifford to arm himself with an ax to work out a bit of stage business, then produces a gun to dispose of Clifford and Deathtrap. The double-cross fails as Clifford has figured out what Sidney planned and has loaded the bullets into a different gun. Clifford secures Sidney to a chair with manacles, unaware they were once the property of Harry Houdini. Sidney easily frees himself, grabs a crossbow and fells Clifford with a single shot. Before Sidney can dispose of the body the storm hits with full force, plunging him into darkness. A flash of lightning illuminates the living room and a fleeting figure scurries through. It is Helga, aware of the mortal danger at the house. A struggle occurs in the dark. Sidney finds a knife while Helga grabs a gun. Clifford regains consciousness and trips both Helga and Sidney. The weapons go flying and a struggle for them ensues that ...
... culminates on stage with actors before a full house, where "Clifford" stabs "Sidney" and both die, leaving "Helga" victorious. The opening night audience erupts in thunderous applause, and at the back of the house stands Helga Ten Dorp, now the happy author of a hit Broadway play called Deathtrap.
Best part of story, including ending:
The twists and turns of Deathtrap, a play within a play... Within a play! The classic cast of five parlor room murder is delightfully turned on its ear. A classic Broadway hit turned movie magic.
Best scene in story:
The quiet interaction between Clifford and Sidney when they first meet, as Myra looks on. Will Sidney kill Clifford? Was he only joking earlier? What would an author do?
Opinion about the main character:
Sidney is an egotisitcal man on a mission. To secure himself financially while searching for his next big hit. That his wife stands in his way is of no consequence.