In 1985, Maine signal orderly Thomas Curry rescues Atlanna, the sovereign of the lowered domain of Atlantis, during a whirlwind. They start to look all idealistic at and have a youngster named Arthur, who is carried into the world with the capacity to talk with sea creatures. Following an attack by Atlantean warriors sent to recuperate Atlanna, who fled Atlantis to escape from a composed marriage, Atlanna is constrained to give up her family and return to Atlantis, entrusting her guide, Nuidis Vulko, with the key getting ready Arthur. Under Vulko's bearing, Arthur transforms into a talented warrior, yet excuses Atlantis in the wake of finding that Atlanna was executed for having a crossbreed kid.
Thirty following three years, sometime after Steppenwolf's intrusion, Arthur confronts a gathering of privateers attempting to seize a Russian Akula-class submarine. Their pioneer, Jesse Kane, kicks the can during the confrontation while his kid David guarantees retaliation.
Meanwhile, Orm, King of Atlantis, and Arthur's stepbrother attempt to convince King Nereus of Xebel to help him with joining Atlantis and attack the surface world for harming the oceans. Nereus raises that if Orm wins with respect to joining all of the four domains, he will get the title of Ocean Master, the official of the most predominant force on earth. Their social affair is frustrated when a Russian Akula submarine ambushes the get-together spot, clearly in retaliation for the past submarine's destruction. Orm wins concerning obliterating it, and the ambush convinces Nereus to join with Orm to secure the oceans. He swears commitment to Orm's inspiration.
His daughter Mera, who has been vowed to Orm, won't help them and journeys to the surface to move toward Arthur for help, procuring his trust by saving Thomas from a wave sent by Orm. Arthur reluctantly goes with Mera to a gathering with Vulko, who urges Arthur to find the Trident of Atlan, a charm old irregularity that once had a spot with Atlantis' first ruler, in order to recuperate his authentic spot as a master. They are caught by Orm's men, and Mera and Vulko get away from cover, while Arthur is gotten.
Arthur is moored and presented before Orm, who denounces Arthur and the surface for Atlanna's death. He offers Arthur an opportunity to leave everlastingly, yet Arthur rather incites him to a duel in a ring of lowered magma. Orm gains the bit of leeway and about homicides Arthur before Mera rescues him. Together, Arthur and Mera journey to the fallen Kingdom of the Deserters concealed under the Sahara desert, where the pike was delivered, and they open a holographic message that drives them to Sicily, Italy, where they recoup the spear's bearings. Meanwhile, Orm meets David, revealing that the submarine that had ambushed them as of late was in sureness a comparable one David seized and that Orm had contracted him to lay hold of the Russian nuclear submarine so he could compose a fake flag attack from the surface, making it seem like Orm's inspiration for war is upheld and making King Nereus side with him. Orm outfits David with a model Atlantean battle suit to kill Arthur, confines Vulko in the wake of revealing learning of his selling out, and pressures the Atlantean Kingdom of the Fishermen to guarantee their dedication to him and his fight against the surface.
Resulting to adjusting Orm's advancement, a totally vigorously clad David rechristens himself as Black Manta and ambushes Arthur and Mera in Sicily, dreadfully hurting Arthur before he is lost a feign to his apparent passing. Mera clinical specialists Arthur's wounds as they search for the spear and urges him to clutch his destiny as ruler. Arriving at their objective, Arthur and Mera experience the Trench, land or potentially water fit brutes, nonetheless, make sense of how to ward them off and show up at a wormhole that transports them to an obscure sea arranged at the point of convergence of the Earth. There, they are startlingly rejoined with Atlanna, who was surrendered to the Trench for her bad behaviors yet escaped and showed up at the obscure sea, where she ended up abandoned.
Arthur faces Karathen, an unbelievable leviathan, and director of the harpoon, and voices his affirmation to make sure about both Atlantis and the surface, showing his worth and recouping the spear, which grants him order over the seven seas. Orm and his accomplices lead a military against the forager forces of the Kingdom of the Brine with the objective of completing Orm's surface battle game plans. As Orm declares himself Ocean Master, Arthur, and Mera, with the assistance of Karathen and the Trench, mediate and lead a huge number of marine creatures in a battle against him. Orm's lovers deny their accommodation to him and clutch Arthur as the certified ruler in the wake of learning he utilizes the spear. Arthur defeats Orm in the fight yet spares his life, and Orm recognizes his predetermination ensuing to discovering Arthur has found and secured Atlanna. Atlanta returns to the surface to rejoin with Thomas while Arthur moves to the situation of eminence with Mera close by.
In a mid-credits scene, David is secured by Dr. Stephen Shin, a specialist and plan researcher focused on the Atlanteans and agrees to lead Shin there as an end-result of his help with his retribution on Arthur.