Ultraman Zearth hails from The Land of Pikari in Nebula Z95. He has a big red face and dislikes dirt, and will go to great lengths to wash it off his hands. His goal is to clean the polluted Earth. He transforms with an electric toothbrush, which is consistent with his hygiene fixation. He's not quite adept at being a superhero, but at least he tries his best.
When he returns to Earth to attend the wedding of his friend in Saipan, Musashi meets a beautiful girl named Shau who claims to come from the bottom of the sea. Just then, Monster Scorpis reappears in the sky above the island and Musashi faces the monster in order to protect the girl. What is the girl's true form? And what is the strange shadowy form that follows the monster Scorpis?
Once again, Musashi has encounter Ultraman Cosmos. Now Ultraman Cosmos has gained some new modes to defeat Scropis. Musashi has joined Team Sea to save the Blue Area. But there is mysterious evil monster, Sandros, who wants to destroy the Earth. Now it is up Musashi and Ultraman Cosmos to defeat Sandros and who’s the other Ultraman?
