Plot synopsis

A priest's younger brother runs off with a woman from a gang.  They live together, she gets pregnant and then both of them get sick from a dangerous disease that is going around.  The baby gets born with serious disfiguring deformities and, with his last breath, the brother asks the priest to care for the baby.  Having no wife and no good place to keep such a child as this, the priest still agrees and cares for and instructs the boy as he would his own son.  Knowing that the boy would attract hostility because of his deformities, he keeps him in the church, and warns him that it would be dangerous for him to go outside because of the way people would treat him.

As was the custom of the city in which the priest lived, an annual festival is underway in which the gangs roam freely through the streets, fascinating people with magic tricks, getting drunk, soliciting sex from strangers and robbing passers-by when the opportunity arises.  Angry about how this kind of behavior had damaged his own family and concerned about the damage it could cause to his community, the priest finally makes up his mind to ask the king to outlaw this festival.

His nephew, having become a very strong adolescent, become restless in his confinement, looks out on the celebration and thinks to himself how much fun it would be to be down there on the streets with all the excitement and activity.  Rebelling against his uncle, he sneaks out of the church and into the crowds.  As his uncle had warned him, the boy is badly abused by a gang and his uncle, hearing about this, at considerable risk to himself, has to go into the crowds to rescue the boy and return him to the safety of the church.  In this he is aided by a young woman in the gang, who feels guilty about the abuse her fellow gang members heaped on the boy.

The priest was not unscathed, however, by this encounter. His close proximity to this attractive young woman, who cared for his son like a mother when others were cruel to him, awakens in him a powerful desire to have her for his own.  He now finds himself consumed with the memory of her presence and struggles to remain faithful to his vows.  She, on the other hand, concerned for the boy and  increasingly uncomfortable with her lifestyle, comes to the priest's church one day to see how he is doing and seek help in finding a different way.  Shocked to see her there, the priest nevertheless recovers himself enough to offer to teach her about the ways of God, but he is unable to conceal the desire that her presence triggers in him.  She, recognizing the signs, flees the church and he, angry at himself and her, warns her never to return.

Torn between his desire for the woman and the demands of his vocation, the priest prays but finds no relief.  Horrified by the power his desire has over him, the priest convinces himself that the woman had used her magic to ensnare him and determines not only to outlaw the festival, but to drive the gangs out of the town and destroy the woman.  He persuades the king to give him a military force for this purpose and sets out on his mission.  Coming to a brothel that is run by the gang members, the priest demands that they turn over the woman to him.  When they refuse, he orders that the place be burned down.  The captain of his military force (who had visited this brothel previously for "recreation") refuses, and the priest, infuriated by the insubordination, strips the captain of his command and has the building burned.

The captain is injured during this encounter and the young woman takes him to the church to seek the boy's help in caring for him and out of a vague hope that the church might provide a sanctuary for them.  When it becomes obvious that she can't stay, she gives the boy a map of where to find her and flees the church.  The priest shows up soon afterwards, suspicious that the boy is sympathetic to the woman, and the boy conceals the captain and denies any involvement with the woman.  Not convinced, the priest decides to trap them by announcing that he knows where she is hiding and will send a force there tomorrow to root them out.  Wanting to warn gang members, the boy and the captain follow the map to their hideout, where they are promptly captured by the gang and sentenced to be hung.  The woman shows up and persuades the gang that the captain and the boy are friends and has them released.  The priest then arrives, having followed the boy and the captain, and he has his force arrest the entire gang.

Having imprisoned both the woman and the captain, the priest then offers to set them both free in return for her company.  Indignant, the woman refuses, and the priest has them both confined together.  The captain tries to persuade her to take up the priest's offer to save her life, while the woman contemplates doing so to save the captain's life.  The following morning, the captain is released and the priest offers the woman one last chance for life on the same terms.  She spits in the priest's face, and he in rage has her burned.  The boy, who has been struggling to find courage to try to rescue the woman, finally runs to the pyre, frees her and takes her back into the church, where she dies after thanking him.  The priest sends the military force into the church to capture them, but they are repelled when the boy pours molten lead from a high window onto them.  The priest, however, is able to enter and he tries to persuade his nephew that all is well and life can continue as it had previously now that the woman is dead, but the boy calls his uncle a monster and throws him out of a high window to his death.

And they close, singing "who is a monster and who is a man?"