After a chance night with sovereign Areno, Leon vanishes and raises their son Finn alone. Years later, desperate to afford the boy's treatment, Leon takes work inside the underwater court and comes face to face with the ruler who never forgot him. Areno is determined to claim the family fate denied him, but jealous Lilith wages war against Leon and his child. As buried bloodlines emerge, Leon discovers his own noble origin, and the enemies threatening them are finally brought down.