Dr. Lily Houghton enlists the aid of wisecracking skipper Frank Wolff to take her down the Amazon in his dilapidated boat. Together, they search for an ancient tree that holds the power to heal – a discovery that will change the future of medicine.

Black Manta, still driven by the need to avenge his father's death and wielding the power of the mythic Black Trident, will stop at nothing to take Aquaman down once and for all. To defeat him, Aquaman must turn to his imprisoned brother Orm, the former King of Atlantis, to forge an unlikely alliance in order to save the world from irreversible destruction.