Ultraman Cosmos is a calm and gentle alien of unknown origin who seeks to protect Earth. Unlike most Ultramen, Cosmos is a pacifist and prefers to resolve his disputes or disagreements by the way of peace.

In the year 2011 the greatest tectonic disaster in the history of mankind has occurred. As a result of the catastrophic earthquakes North and South America, Eurasia, Africa and Australia have sunken underwater while the Japanese islands remain untouched.

For 50 years, "Outer Man" has been a cultural icon in Japan, a superhero TV series as ingrained in the national psyche as Ultraman. Generations have grown up watching the heroic Outer Man defend Earth from the monstrous Sylvie Seijin. But the line between fiction and reality blurs when a giant alien, identical to Outer Man, descends upon Tokyo.

Taishô's father is a supermodel cat, and everybody believes that Taishô will be a supermodel as well. His family has great expectations of him, because he is the eldest son, but he can't bear all the pressure and runs away from home. Unfortunately, he has no clue how to survive on his own, having always been fed and pampered as a model cat. Taishô passes from one job to another, homeless, until he finds his place in a noodle shop, where he becomes a successful cook.

When military experiments go haywire and trigger an atomic bomb, the consequences are of epic proportions. A monster arrives in the midst of the nuclear fallout, and Japan's defenses are helpless against it. Mankind's only savior is an irradiated water goblin from Japanese folklore called the "Death Kappa." The two rival monsters must go head-to-head in the ultimate battle between good and evil!