Trilogy is an anthology film of three adaptations of Truman Capote short stories: Miriam, Among the Paths to Eden and A Christmas Memory. It was listed to compete at the 1968 Cannes Film Festival, but the festival was cancelled due to the events of May 1968 in France.

Tina Balser is a bored New York housewife-mother married to Jonathan, a pompous, social-climbing lawyer who ridicules her in front of their children, criticizing everything she does or wears. She begins an affair with George Prager, a dashing, successful, and blatantly sadistic writer.

Doc Holliday travels to Tombstone, Ariz., with prostitute Katie Elder. Although the trip is difficult because Doc is ill with tuberculosis, they eventually reach their destination, where Holliday is reunited with his old friend Marshal Wyatt Earp, who has been clashing with the Clanton gang. Tensions between Earp and the Clantons rise until their infamous final showdown brings it to a head.

Two drifters, of widely varying backgrounds, rustle cattle and try to avoid being caught in contemporary Montana.

A small-town police chief investigating a murder is offered help by a self-described psychic. However, when the chief discovers that the "psychic" is in possession of information known only to the police, he suspects that the man may be more involved in the case than he lets on.