Pirate city-states hold the Tidal Rite: every three years, a noble girl is sacrificed to wed sea god Nereus and contain dark god Cthaken.
To save his sister Lian, Laren, who carries Cthaken’s bloodline and can shift his face, disguises himself as the sacrificial bride for three years in exchange for freedom and a fleet.
In the sea palace, Nereus favors siren Ison, ignoring Laren’s suffering amid constant sabotage.
Once free, Laren flees to Free Port, falls in love with adventurer Karen, and rejects the remorseful Nereus who only learns his secret after he leaves.
The cultist Evan frames Nereus for Karen’s death to awaken Cthaken within Laren. The dark god breaks free and ravages the lands. Odin’s gods destroy Cthaken’s core, leaving Laren near death.
Nereus casts forbidden time magic to reset reality. The brutal sacrifice ritual vanishes. In this new world, Laren lives a cherished, peaceful life. Nereus gives up his longing, sends Laren to Karen, and returns to the sea alone with all his regret.
