WARNING: The following contains spoilers for director James Wan's Aquaman, opening Friday nationwide.

Aquaman essentially picks up where Justice League left off, with Jason Momoa's Arthur Curry still wrestling with his destiny as the king of Atlantis. As his half-brother, Orm readies to bring war to the surface world, the Aquaman goes after the all-powerful Trident of Poseidon to stop him.

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That leads to the hero, accompanied by Mera (Amber Heard), braving the undersea kingdom of the monstrous Trench to arrive at the Hidden Sea at the Earth's core, where they find not only the tomb of the legendary Atlantean King Atlan but also Arthur's mother Atlanna (Nicole Kidman), long believed dead. As Arthur undergoes a trial of character to see if he's worthy of the weapon, his half-brother Orm (Patrick Wilson) forcibly recruits an undersea army that will enable him to launch his war against the surface world. That leads to an action-packed finale that's arguably the best we've seen in the DC Extended Universe.

RETURN OF THE KING

Aquaman

With the seven undersea kingdoms splintered for centuries, all Orm requires to command the combined army of the oceans against the surface is a majority vote that will decree him the Ocean Master. With Dolph Lundgren's King Nereus already pledging Xebel's loyalty, Orm forces the Fishermen into the alliance with a brazen assassination, and now attacks the Brine to force the kingdom to submit.

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However, as Orm is about to the kill the Brine King, Arthur appears with his new trident, having convinced its keeper, the kaiju-like Karathen, he is indeed Atlan's successor. Aquaman saves the king, and summons all life in the ocean -- whales, sharks, dolphins and even the monstrous Trench -- to bring down Orm's army. Atlantis' forces are outnumbered, leaving Arthur to face Orm in single combat to determine who should rule the seas.

A NEW DAWN

Arthur and Orm, wielding the trident that belong to his late father Orvax, battle atop the massive Atlantean royal ship. The fight ends with Arthur using tricks he learned as a boy from his mentor, Vulko (Willem Dafoe), to break Orm's trident and defeat his half-brother in front of the rulers of Xebel, the Fishermen and the Brine, and the Atlantean army. But when Orm begs to be killed, Arthur instead shows mercy.

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Aquaman makes it clear these savage ways are no longer permissible, and wins over the kings of Xebel, the Brine and the Fishermen. They swear fealty to him as he indicates unity is the only way to usher in a new era of peace.

IT STARTS AND ENDS WITH FAMILY

Queen Atlanna arrives and forgives Orm for being misguided by his father. Most of his hate was driven by the belief that she was killed by the Trench after being sacrificed as punishment for giving birth to Arthur, a child of land and seas. Vulko instructs Arthur's new soldiers to take Orm away, but the triumphant king makes it clear that, whenever his half-brother is ready, there's a possibility of healing their rift.

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The film ends as it began, focusing on the love between Arthur's parents, the lighthouse keeper Tom Curry (Temuera Morrison) and Atlanna. He waited on her every day since she returned to Atlantis, hoping she'd return, and finally she has. As Aquaman focuses on life in Atlantis and his own budding romance with Mera, his voiceover makes it clear this is how both worlds should live -- together as one.

Directed by James Wan, Aquaman stars Jason Momoa as Aquaman, Amber Heard as Mera, Patrick Wilson as Orm, Willem Dafoe as Nuidis Vulko, Yahya Abdul-Mateen II as Black Manta, Temuera Morrison as Thomas Curry, Dolph Lundgren as Nereus and Nicole Kidman as Queen Atlanna. The film is in theaters now.