It has been two years since our heroes last banded together to fight the menace of the Blue Hun. Now another threat to the world is on the rise. Sea King receives an urgent message from King Neptune in Atlantis. He and some of the others come to his aid while Dan Urich and the rest of the group venture to the Island of Vipralia to conduct a business deal. They are unaware of the dangers they will encounter there. Meanwhile, back at the Cincinnati, Ohio office of the Urich Foundation another superhero emerges. Who is The Sword? The answer can be found in the pages of Project: Hero Atlantis Under Attack.