In the apocalyptic age of ocean navigation, Leo, a lowly sailor, is cursed for refusing to sacrifice to the war god Ares. On the brink of death, he awakens the sealed sea god Poseidon, obtaining a dark-gold trident and a ghostly deep-sea battleship. To lift his curse and fend off divine tides, Leo hunts sea monsters and sacrifices enemy vessels to upgrade his warship. After saving Talia, a trial-taker of Athena, he uncovers the gods’ plot to usurp the sea god’s authority. He destroys three divine sea spikes set by Zeus, merges with the sea god’s primordial essence, and steers his dreadnought to wage vengeance on Mount Olympus.