Newlyweds Arthur Curry and Mera reign as King and Queen of Atlantis. Mera's sister Siren, jealous over her relationship with Arthur, teams up with David Kane to destroy Atlantis and kill Arthur and Mera. Kane, now known as Black Manta, has been plotting revenge against Arthur ever since Arthur failed to rescue his father, a known pirate. Arthur and Mera must fight to defeat Black Manta and Siren, save Atlantis, and restore peace to the seven seas.