Man-At-Arms has built a new dam around the kingdom of Eternos, to block off the Eternian ocean and prevent flooding. However, some of his food ships have gone missing, and while flying over the ocean to investigate, Buzz-Off has noticed a strange volcanic island which is not marked on any map. Adam, Cringer, Orko, Man-At-Arms, Teela and Buzz-Off go to investigate further. It soon turns out that Skeletor is the source of the problem, using a floating island to capture the food ships, planning to starve the Eternians then smash through the dam to flood Randor's kingdom! Can the heroes stop him before he succeeds?