Shibasaki Kaori is a doctor. Her patient that she was having an affair with dies. Kaori is suspicious of the patient's son Kido Takashi about the death. Noguchi Tomomi is a single mother. She is excited in experiencing love for the first time in 7 years. Harada Saeko is in conflict with her husband Harada Satoshi about having a child. Mizushima Juri insists on having freewheeling romance. She feels excitement with meeting a woman. These four women's lives connect and an unexpected story begins.

Aliens have been emigrating to Earth secretly, but only a handful knows about this truth. Living in such a society, the main character Hiroyuki Kudo begins working at a private security organization E.G.I.S. (Enterprise of Guard and Investigation Services). The organization takes care of cases related with aliens, and Hiroyuki works day and night to protect peace. However, there lies a huge secret in him, which he himself is not aware of. He carries Ultraman Taiga’s “particle of light”. The new story begins as Taiga’s powers revive from Hiroyuki’s body!