Bethlehem, AD0. Brian Cohen is born in a stable next-door to Jesus Christ.
Jerusalem, 33 years later. The adult Brian and his mother attend Jesus's Sermon on the Mount, but Mrs. Cohen finds it boring. They leave to attend a public stoning. After the stoning, Mrs. Cohen reveals that Brian's father is a Roman, much to Brian's disgust. Later, while working as a snack seller at the local gladiatorial coliseum, Brian meets The Peoples Front of Judea (PFJ), a terrorist organisation dedicated to liberating Judea from Roman occupation. The PFJ's leader, Reg, offers to let Brian join the group if he completes an initiation task: he must paint 'Romans Go Home' on the walls of Pontius Pilot's palace. Brian agrees. Brian and Judith, the only female member of the PFJ, exchange flirtatious glances.
Brian is caught daubing the slogan on the palace by centurions but escapes. He is inducted into the PFJ and joins the group on a mission to kidnap Pilot's wife. The mission fails; Brian is captured and dragged before Pilate, who sentences him to crucifixion. Pilate argues with his men over his speech impediment and in the confusion Brian escapes. To avoid recapture, he poses as a preacher, and is unwittingly mistaken for the messiah by a small but ever growing crowd. In spite of Brian's protestations, the crowd follows him through Jerusalem. He eventually escapes the crowd and returns to his mother's house.
That night Brian sleeps with Judith. The following morning, the crowd has besieged Brian's mother's house. Brian evades their attentions by slipping out by the backdoor, but is arrested by centurions and sent for crucifixion.
In keeping with a Passover tradition, Pilot addresses the Judeans and agrees to free a Jewish prisoner as a goodwill gesture. The crowd, ridiculing Pilate for his inability to pronounce the letter 'r', asks for the release of Brian.
Brian, already nailed to a cross on the crowded Golgotha, is visited by the PFJ, who thank him for his martyrdom, but make no effort to free him. A centurion arrives with Pilate's decree to release Brian, but the prisoner on the cross next to him claims he is Brian, and is released in his place. Brian is visited by Judith and his mother, neither of whom attempt to rescue him. Brian is told to look on the bright side by a man on the cross behind him, who leads the condemned prisoners in a sing-along.
