The plot is based on the Basque folktale version of The Smith and the Devil, as collected by Father Joxemiel Barandiaran.

The nearby villagers avoid the forge due to rumours that Patxi murdered his wife and kidnaps young children.

The villagers mistrust Ortiz as the government melted down all their metal during the war to make weapons, including their church bell.

Benito, a boy from the village, steals a letter proving Ortiz is searching for gold that vanished during the war.

Usue, an orphan girl with a burn scarred face, is bullied by Benito who throws her doll over Patxi's fence.

Inside the forge, she finds a boy captive in an iron cage, who begs her to steal Patxi's ring of keys to free him.

Enraged, Patxi burned Usue’s face and murdered her father, while Maite, grief-stricken, hanged herself.

Ashamed, Patxi gave Usue to the priest as an orphan, along with a replacement bell he forged for the church.

Sartael agrees as he wants revenge against Alastor, but remarks that Patxi will need more than his small golden bell to survive Hell.

Patxi reveals that the giant bell that he forged for the church is made from the very gold Ortiz was looking for.

Sartael kills Patxi with his pitchfork, taking them both to the gates of Hell where thousands of damned souls are waiting to enter.

Patxi sends Usue back with Sartael while he decides to remain in Hell to search for Maite.