In the harsh post-war years' Catalan countryside, Andreu, a child that belongs to the losing side, finds the corpses of a man and his son in the forest. The authorities want his father to be made responsible of the deaths, but Andreu tries to help his father by finding out who truly killed them. In this search, Andreu develops a moral consciousness against a world of adults fed by lies. In order to survive, he betrays his own roots and ends up finding out the monster that lives within him.

Barcelona, 1983. Agustí Martorell is a left-wing lawyer, atheist and former anti-Franco fighter, who discovers that his 15-year-old daughter Esther, influenced by the optional religion classes of Mossèn Parcerisas, a progressive priest and post-councillor, has converted to Catholicism and was secretly baptized.