The first Ultraman of the Reiwa era, Taro's son, Taiga, is here! There are many aliens living secretly on Earth. But this fact is little known. In such a society, the protagonist Kudo Hiroyuki works for the civilian security organization "EGIS" that mainly resolves disputes caused by aliens, and works hard for peace every day. But he hides a secret that he doesn't even know, that is, the light particles of Ultraman Taiga attached to him. The moment Ultraman Taiga wakes up in Hiroyuki's body, a new story begins...