Attuma leads his fellow Atlanteans into riding a tidal wave into Manhattan as part of his plot to conquer the surface world. Iron Man engages Attuma while the other Avengers fight his soldiers. Attuma then heads into the flooded subways as Iron Man changes into his underwater armor to follow Attuma. Captain America and Hawkeye discover strange devices as Iron Man detects a lot of them underground, as they are set off in a plot to sink Manhattan by destabilizing the bedrocks of Manhattan. Attuma and his soldiers end up fighting Captain America, Hawkeye, and Hulk, while Iron Man, Falcon, and Thor hold back the tidal wave with an energy barrier. Hulk charges towards Attuma as Thor helps to fight Attuma's soldiers. Hulk then engages Attuma, where they are evenly matched until Attuma punches Hulk through the energy barrier that Iron Man and Falcon created to hold back the tidal wave. Thor and Iron Man then attack Attuma, where their attacks could not harm them. When Attuma and his soldiers retreat into the oceans to find out why Manhattan is rising, they alongside Iron Man find Hulk holding up the island. While Hulk is buying the Avengers some time, the other Avengers fight Attuma, who then escapes into the ocean to prevent Hulk from succeeding. Attuma has the advantage in the water over Iron Man and Thor until Hulk gets angry enough to prevent Manhattan's sinking as well as throwing a large rock at Attuma. Attuma is thrown onto land as Hulk manages to defeat him. Following Attuma's defeat, Iron Man repairs the bedrocks beneath Manhattan.
Attuma's advisor Lady Zartra and the Atlanteans with her are getting tired of Attuma's tyranny, and plan to use the Serpent Crown in order to use Giganto against him. After a misunderstanding between the Avengers and Lady Zartra's group, Attuma arrives with his soldiers and uses an eel to snatch the Serpent Crown, where he unleashes Giganto on both groups. With the help of Hawkeye using special sonic arrows to disrupt the control on Giganto, the Avengers reclaim the Serpent Crown, free Giganto, and defeat Attuma. As Lady Zartra and her group are now free from Attuma's tyranny, the Avengers contact S.H.I.E.L.D. to have Attuma extricated to the surface world to stand trial for his crimes against the surface.
Spider-Man and the Avengers fight Attuma at the beach. Attuma is defeated when Spider-Man punches Attuma far out into the ocean.