Aquaman (or Aquaman: Throne of Atlantis in some countries) is the first solo film featuring Liam Hemsworth as Arthur Curry/Aquaman. When Atlantis begins to attack the surface it is up to Arthur Curry aka Aquaman to reclaim the throne, however there is something much bigger going on in the underwater city. It is part of the Doomverse.
While manning Curry Lighthouse, Tom Curry spots someone floating in the water during a storm. He motors out into the storm and "saves" Atlanna who he thinks is drowning. He tends to her and she is very appreciative, the two have a natural connection. After spending just two days together, Tom wakes up and finds that Atlanna had gone after a night of passion in which the pair slept together. Nine months later, Atlanna returns, in the early hours of the morning, with a baby and leaves him in Mercy Reef for Tom to find and raise. Ten years later, Arthur starts asking his father why he is so different and it's revealed that Arthur can breathe under water, is much stronger than a regular boy of his age and can telepathically communicate with marine life. Years later, a teenage Arthur, grieving his father's death, inadvertently causes Black Manta's father's death, believing Manta to be responsible for Tom's death.
Present day, Arthur is visited by Nuidis Vulko who begs him to return to Atlantis because, as the Atlantean advisor, Vulko doesn't believe Orm, Arthur's half brother is worthy to be king. By this stage Arthur is married to Mera and living with her in Curry Lighthouse. He refuses to return to Atlantis until some Atlanteans begin to attack the surface world unprovoked. Arthur and Mera counter these attacks, Mera only doing so to support her husband not because she wishes to protect humans who have always been hostile towards her for being different, and Arthur discovers that the King of Atlantis had died so his replacement - Arthur's half-brother Orm - ordered the attacks as he blames the surface for the King's death due to the pollution they have caused to the ocean.
This forces Arthur to return to Atlantis, making Arthur the rightful king as he is Orm's elder. The Atlanteans are initially hostile towards their new King who is a stranger to them and refuses to go to war with the surface to avenge their former King's death. Orm supports Arthur's choice but then they hear of another attack on the surface despite Arthur forbidding anyone to do so. Arthur returns to the surface and tries to prevent bloodshed between the humans and Atlanteans (who are severely outnumbered). Then Manta shows up. Meanwhile, in Atlantis, a group of Atlanteans try to abduct Mera who stayed behind but she uses her hydrokinetic powers to break free and seeks refuge with Orm. Vulko tries to speak with her but Orm refuses to let him see her and then tells Mera that it was Vulko who ordered the attacks. Aquaman fights Manta aggressively with the Trident of Neptune but Manta fights just as aggressively back until he releases a heat beam from his helmet, driving Aquaman back into the ocean and back to Atlantis.
In Atlantis, after spending some time in the infirmary having his burns tended, Arthur is given some orange scale armor by Vulko to protect his flesh from Manta's heat ray. This is when Vulko gets taken away by Atlantean guards for ordering the attack on the surface. Orm publicly declares that it was Vulko who defied the King and orders him to be taken to the Aquarium (Atlantean Prison). Arthur intervenes, viewing Vulko as a substitute father figure. Orm begins to rally the Atlanteans against Arthur, claiming that Arthur would rather live on the surface than defend his own people. Instead of taking Arthur and Vulko to prison they are cast out of Atlantis. Mera tries to follow but Orm doesn't allow her to leave. Arthur takes Vulko to Curry Lighthouse where Vulko tries to convince Arthur to return and try to win them over, Arthur struggles to understand why Vulko is still so loyal to them even after being exiled. However, he had already planned on returning for his wife.
In Atlantis, Orm attempts to seduce Mera, stating that she would make a fine queen, standing by his side opposed to Arthur's. When she refuses she gets taken away by Manta-Men who begin to storm Poseidonis, subduing any Atlanteans who disagreed with Vulko and Arthur's exile. Orm announces to Atlantis that he found the man who attacked them on the surface and has struck a deal with him. Black Manta then steps forward. Informing them that "King Orm" has enlisted his help to make Atlantis safer and with his help there won't be any more damage caused to them. Two young Atlanteans, Garth and Tula, realise what is really happening. Garth asks Tula if she really thinks going against Orm's orders to which Tula responds "Orm may be my half-brother but even I know that this is wrong, he needs to be stopped before this goes even further." The duo split up and Tula infiltrates the Atlantean Royal Palace with ease as the guards let her in due to her heritage. She locates Mera who has already dispatched the guards with her hydrokinesis as Tula arrives. Meanwhile, Garth travels to Curry Lighthouse to inform Arthur of what is happening in Atlantis. When he arrives Arthur is already preparing to return, wielding his Trident.
Mera and Tula start taking out Atlantean guards and Manta-Men as they take any Atlanteans who don't agree with Orm to the Aquarium. Garth and Arthur return to Atlantis. Manta-Men spot them and advance on the pair, Aquaman sets sharks on them, revealing he brought back up as an army of marine life follow him including sharks, whales, squids and octopuses. Aquaman sets the marine life on the rest of the Manta-Men and seeks out Orm, finding Mera and Tula in the Palace with the same agenda. Garth and Tula are told to help the Atlanteans while Arthur and Mera look for Orm. They find Manta instead who claims to have used Orm to find Atlantis and Arthur so he can finally get his revenge.
The two battle while Mera continues to search for Orm. Aquaman and Manta have a long, violent and bloody battle, Aquaman ultimately getting the upper hand, his trident at Manta's throat. He apologises to Manta about what happened with his father and tells him to return to the surface and that if he ever returned Aquaman wouldn't hesitate in killing him. Manta gets to his feet and tries to blast Aquaman, Aquaman smashes Manta's helmet and knocks him out then tells two Manta-Men they will be spared if they take him away. They drag their boss away and they leave in Manta's Sea Saucer.
Elsewhere, Mera finds Orm, who tries to convince her that he was forced to do it by Manta, that it was all Manta's idea, he then attacks Mera when it appears she doesn't believe him. Mera uses hard water constructs to fight Orm until Arthur steps in soon followed by Tula, Garth and many Atlanteans. Orm is outnumbered and surrenders. Arthur exiles Orm and becomes officially coronated as King Orin the Second (his Atlantean name that his mother gave him). Aquaman tells the Atlanteans that despite his position he still has ties to the surface and in his absence, his Royal Advisor, Vulko, would be left to rule. Mera, uncomfortable with the hostility towards her for being from Xebel decides to stay in Curry Lighthouse rather than in Atlantis.
Mid-credits: Exiled and furious, Orm adopts a "costume" and a new persona - the Ocean Master and vows to reclaim what is rightfully his.
Post-credits: Some time later, Black Manta looks over a new set of plans when a voice says "You've made quite the impression 'Black Manta', you went toe-to-toe with 'Aquaman' and live to tell the tale." A bald man is seen from behind contacting Manta from an undisclosed location. Black Manta asks who he is, the man is revealed to be Lex Luthor who then recruits Manta into the Legion of Doom.
- Liam Hemsworth as Orin/Arthur Curry/Aquaman
- Amanda Righetti as Mera
- Brendan Gleeson as Nuidis Vulko
- Alexander Ludwig as Orm/Ocean Master
- Mekhi Phifer as Black Manta
- Kevin McKidd as Thomas "Tom" Curry
- Cassidy Freeman as Atlanna
- Josh Peck as Garth
- AnnaSophia Robb as Tula
- Jon Hamm as Alexander "Lex" Luthor