Aquaman, the heir to the Atlantis throne, must step forward to lead his people and prevent a war between the underwater kingdom and the surface world. Along the way, he discovers his true destiny and fights against his half-brother, who seeks to bring destruction to both worlds.

Black Manta seeks revenge on Aquaman for his father's death. Wielding the power of the Black Trident, he becomes a formidable foe. To protect Atlantis, Aquaman forges an alliance with his captive brother. They must defend the kingdom.