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.

During summer vacation on Long Island, three young people--a girl and two guys--become so close that they form a sort-of threesome. When an uncool girl tries to infiltrate the trio's newly found relationship, they construct an elaborate plot that has violent results.

Teenager David Clemens develops a hysterical fear that he will die if he comes into physical contact with another person. Perturbed, David's overbearing mother places him in a home for mentally disturbed young people, but David remains withdrawn from the other patients and his psychiatrist. Over time, however, David grows interested in 15-year-old Lisa, who suffers from multiple personalities – one who can only speak in rhyme, and the other, a mute.

A man spends a summer day swimming home via all the pools in his quiet suburban neighborhood.