Once home to the most advanced civilization on Earth, the city of Atlantis is now an underwater kingdom ruled by the power-hungry King Orm. With a vast army at his disposal, Orm plans to conquer the remaining oceanic people -- and then the surface world. Standing in his way is Arthur, Orm's half-human, half-Atlantean brother and true heir to the throne. With help from royal counselor Vulko, Arthur must retrieve the legendary Trident of Atlan and embrace his destiny as protector of the deep sea.