Sai

A residential area near the sea in Kanagawa. The owner of the house, Sawada, died in an unfortunate accident that occurred in the garage of his house. After hearing the story from Sawada's wife Akari (Yamada Maho), Domoto (Nakamura Anne) suspects that it was just an accident and begins an investigation with his junior detective, Kikuchi (Miyachika Kaito). Meanwhile, Iida (Takehara Pistol) tries to find the invisible person involved in the series of suspicious deaths that Domoto is investigating. Then, a "man" appears before them.

Misae (Maki Sakai), a housewife, is invited by her friend Ryoko (Asuka Kurosawa) to start exercising at the public pool, but soon finds out a secret about her husband Kazuhisa (Ryushin Tei). Meanwhile, Domoto and Kikuchi are closing in on the existence of a "man" behind several suspicious deaths that were thought to be unrelated. What is the true identity of the "disaster" that strikes people, and who is the "man"?