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?

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.

Gamu Takayama is a 20 year old member of an organization called Alchemy Stars. After a monster known as C.O.V. attacked the Earth, Gamu falls through a portal of light and meets the giant: Ultraman Gaia, who gives him his powers. Later, when Gaia was in trouble in episode three, another Ultraman, Ultraman Agul appeared. Can they save the Earth? Who is Agul, is he friend or foe? Later in the series it is seen that Agul, too, is a being of justice, but only protects the Earth, not humanity. The conflict between the two later leads to a duel, opening a wormhole that allows a giant beast to reach Earth. What will happen then?

进入21世纪，世界各地灾难频发，更有各种空想怪物惊现世间，引出无数的灾难，而人类文明也面临覆灭的危险。在这个关键时刻，DASH小组的热血青年男女站在人类的最前端，以他们微弱的力量包围着地球。充满正义感的青年东马快斗（青山草太 饰）志愿加入DASH，可是却未能通过相关测验。某天，两只怪兽现身日本，并相互缠斗。危难当前，地球人得到来自M798星云的正义使者麦克斯奥特曼的帮助。新世纪的正义与邪恶的战争由此拉开序幕…… 本系列39话共集结了金子修介、八木毅、実相寺昭雄、梶研吾等11名导演和NAKA雅MURA等在内的18名编剧共同完成。