The film opens with an announcement: a rich industrialist is giving up his factory to his workers. We learn later that Paolo does so after being seduced by a handsome young man, who as a guest at his villa also seduced his teenage son and daughter, his wife and his maid. The young man, played by Terence Stamp, could be God or the devil, but the encounter with him changes every member of the bourgeois family.
The maid Emilia returns to the country, where she refuses to eat or drink, until two children cook a meal of roadside weeds for her. She is next seen by the villagers levitating miraculously above a house, before she is willingly buried alive, her tears feeding a puddle.
The son Pietro turns to painting, to recapture the ecstasy of the encounter, but he knows every artistic attempt is a failure and a fake. The mother Lucia picks up young men in her car, and suffers sexual disappointments. The daughter Odetta falls into a comatose state, clutching what appears to be an object given her by the visitor. After he has been seen cruising a male hustler at Milan's main train station, Paolo strips himself completely naked in public. He is next seen walking barefoot, as if in penance, over a barren landscape.
In delineating the different ways in which the family copes with the crisis, Pasolini lays bare the desperation and self-delusions of the bourgeosie: in Art, Sex, and Religion. The film does not depict people with much psychological realism. The drama is symbolic, a mode that turns almost emblematic in film, as does the deserted factory complex that frames the narrative.