Many years ago, the Queen of Atlantis (Nicole Kidman) and humans became acquainted with each other, and together gave birth to the fruit of love-Arthur Curry (Jason Momoa), who was later called the Sea King by land people. While growing up, Arthur received strict training from the underwater mentor Vico (William Dafoe) and always longed to visit his mother. However, as a mixed-blood bastard, this was an extravagant wish. At the same time, Arthur's half-brother Ome (Patrick Wilson) becomes king of Atlantis. He is dissatisfied with the poisoning and pollution of the sea by land humans, so he plans to join forces with other underwater kingdoms to launch a full-scale war on land. In order to stop his ambitions, Vico and Om's fiancee Meira (Amber Heard) take Arthur to the underwater world. Fate pushed Arthur to find the long-lost Trident and build a more enlightened underwater kingdom...