The film has no plot, in the normal sense of the word. There are two central characters, an unnamed man and woman. The chronology of the film is disjointed: for example, it jumps from "once upon a time" to "eight years later" without the events changing. It uses dream logic that can be described in terms of Freudian free association, presenting a series of tenuously related scenes that attempt to shock the viewer.
The film opens with a scene in which a woman's eye is slit by a razor. The man with the razor is played by Buñuel himself. In subsequent scenes, a man's hand has a hole in the palm from which ants emerge (a literalization of the French phrase "ants in the palms," meaning that someone is "itching" to kill or is motivated by sexual desire); an androgynous blind woman pokes at a severed hand in the street with her cane before being knocked down by a car; a man fondles a woman, who resists him violently, and then he drags two grand pianos containing dead and rotting donkeys, the tablets of the Ten Commandments, and two live priests (Dalí plays one of the priests in this scene); the man's father (played by the same actor as the man himself) arrives to punish him, but the man eventually shoots him with two pistols that appear seemingly out of nowhere; and a woman's armpit hair attaches itself to a man's face.
At the end of the film, the woman walks out of the apartment building, and meets another man on the beach (also played by Dalí). They seem to be happy, but the final shot shows two figures (apparently Mareuil and Dalí) buried in sand, dead, and "consumed by swarms of flies" according to Buñuel's original script. However, this latter special effect was left out due to budget limitations.