A wise woman prophesies to the king that his wife will bear a daughter and Licinio's widow (Elisa Cegani) a son, that the two will fall in love, and the son take the kingdom from Sedemondo. When he gets home, he is told that his wife has given birth to a boy (the daughter having been switched with the child of Licinio) and so believes the prophesy to be invalid. He raises both the boy Arminio and girl Elsa. After some strife between Sedemondo and Arminio, the king orders Arminio to be taken to the gorge and slain.