It stars Paul Frankeur, Laurent Terzieff, Denis Manuel, and Daniel Pilon, with Alain Cuny, Michel Piccoli, and Delphine Seyrig in supporting roles.

Buñuel later called The Milky Way the first in a trilogy about "the search for truth", along with his subsequent films The Discreet Charm of the Bourgeoisie and The Phantom of Liberty.

Two French vagrants, Pierre and Jean, decide to take the pilgrimage route from Paris to Santiago de Compostela along the traditional Way of St. James.

As they walk along a roadside near Fontainebleau, they encounter a caped clergyman who tells them to sleep with a prostitute and have children with her as in the Biblical account of Hosea and Gomer.

The pilgrims unsuccessfully seek food at an expensive restaurant, where the manager is explaining to his staff the controversy of the divinity of Jesus as debated during the First Council of Nicaea.

As a class of young girls recites heresies and proclaim them "anathema", one of the pilgrims imagines a band of anarchists executing the Pope.

These new men leave the pilgrims and travel to a nearby abbey, where they watch the official desecration of a priest's grave because of the posthumous discovery of his heretical writings regarding the nature of the Trinity.

Luis Buñuel and his screenwriting partner Jean-Claude Carrière wrote the first draft for The Milky Way in 1967 at the Parador Cazorla in the Andalusian mountains.

The two main characters often encounter individuals in the dress of various time periods throughout history, or historical events take place in the modern setting of the film, including scenes from the life of Jesus Christ.

"[3] Often, the encounters involve conversations or arguments regarding a specific Catholic doctrine or heresy and are intended to show the absurdity of making absolute statements about such topics as a "matter of fact".