Buneul continues his confrontation with Catholicism, concerning himself in this film primarily with issues of doctrine and questions of heresy. The surface tone of the film is comic, but below that, there lies an urgent desire to come to terms with Catholic theology. On their pilgrimage to Santiago di Compostella, two tramps encounter a mysterious traveller whose prophecy that a prostitute will bear their children, is later seen to be an accurate one. They continue on their way, and their journey becomes a series of incidents which highlight both the life of Christ and the claims of heretics who assert refutations of Catholic doctrine. A sixteenth century priest, arguing for his faith, turns out to be an escaped mental patient; a shepherd, speaking Latin, introduces us to a fourth century erotic ritual; visions of children reciting the catechism become images of anarchists executing the Pope; a Jansenist and a Jesuit, indulging in a verbal duel, recite their beliefs taken verbatim from seventeenth century texts; two students, responding to a Bishop's outlining of the doctrine of the Trinity, shout heresies. And so, moving through time, we explore Transubstantiation, the Immaculate Conception. Christ as both God and Man, The Trinity, the Origins of Evil, and Free Will.