Having met on a train, a smooth-talking psychotic socialite shares his theory on how two complete strangers can get away with murder to an amateur tennis player — a theory he plans to test out.

Larry Donner, an author with a cruel ex-wife, teaches a writing workshop in which one of his students, Owen, is fed up with his domineering mother. When Owen watches a Hitchcock classic that seems to mirror his own life, he decides to put the movie's plot into action and offers to kill Larry's ex-wife, if Larry promises to murder his mom. Before Larry gets a chance to react to the plan, it seems that Owen has already set things in motion.

A woman seduces a professional golfer, then offers to kill his opponent if the golfer will kill her psychiatrist, who wants her committed.