Arthur Curry (Jason Momoa) becomes the king of Atlantis after defeating his brother Orm and claiming the Trident. Meanwhile, the sea pirate David sets out to avenge his father's death, which he blames on Arthur. In a cave, David discovers the Black Trident, an artifact of immense power. How does David change after acquiring the Black Trident? What are the powers he gains? The story unfolds around how Arthur confronts the misdeeds of David.