Gamu Takayama is a 20 year old member of an organization called Alchemy Star. 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.
A jellyfish-like monster with incredibly destructive powers seems to be immune to conventional attacks
A mysterious typhoon seems to be caused by something other than the weather, and it's up to XIG to prevent the unnatural disaster from wreaking too much havoc.
Fujimiya awakens the monster, Zonnel, with the intention of stopping an asteroid headed towards the Earth.