In Aquaman 3, Arthur Curry (Jason Momoa) must face his greatest threat yet as the seven kingdoms are thrown into chaos by the reawakening of Necridus, a mythical sea god imprisoned centuries ago. Freed by extremist rebels seeking to restore the old order, Necridus declares war on both the surface world and Atlantis. With Queen Mera (Amber Heard) weakened from childbirth, Arthur turns to an uneasy alliance with Black Manta (Yahya Abdul-Mateen II), who seeks redemption after his father’s vision appears in a sacred relic.

As Necridus gains power, Atlantis begins to collapse under the weight of civil unrest. Arthur must wield a reforged trident—crafted from the bones of sea titans—and lead an army of outcasts. In a climactic battle beneath the Mariana Trench, he sacrifices part of his power to reseal Necridus. The film ends with Atlantis restored, but Arthur stepping away from the throne to raise his son on land—marking the dawn of a new legacy.