The subject is taken from ancient Greek history. Leonidas, king of Sparta, was usurped by his son-in-law, Cleombrutus. When Leonidas returns looking for revenge, his daughter Chilonis pleads for her husbands life. Leonidas is moved by her tears, and commutes Cleombrutus's death sentence to banishment. Torn between between filial piety and conjugal love, Chilonis decides to follow her husband in exile with their two young children.