Once home to the most advanced civilization on Earth, 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 Curry, Orm\'s half-human, half-Atlantean brother and true heir to the throne.
Henry struggles to bond with his estranged son, Gabriel, who suffers from a brain tumor that prevents him from forming new memories. With Gabriel unable to shed the beliefs and interests that caused their physical and emotional distance, Henry must learn to embrace his son\'s choices and try to connect with him through music.