Sai

Yuri Kitagawa (Sena Nakajima), a high school student studying for entrance exams, spends her days alone, troubled by her tenuous family relationships. Her love life is not going well, and she is struggling to choose her future career due to her family's financial situation. One day, a "certain man" (Teruyuki Kagawa) appears before Yuri. Yuri begins to open up to the man, but soon a terrible "disaster" befalls her.

Kuramoto (Matsuda Ryuhei), who works as a mechanic at a transportation company in Fukuoka, has a guilty past. He caused an accident while driving under the influence of alcohol, resulting in the death of someone. Because of that incident, his wife Kana (Sato Miyuki) left him, and Kuramoto, who still has feelings for her, tells his mother-in-law Ikuko (Kamino Misuzu) that he has quit drinking and reformed. Kuramoto faces his own mistakes and tries to move forward little by little. However, a "man" appears before him.

Iori (Uchida Chika), a cleaner at a shopping mall, is shy and unable to find hope in life. One day, Iori meets and interacts with Minagawa (Fujiwara Kisetsu), who works at a barbershop in the same shopping mall. Minagawa also has a secret that he cannot tell anyone, and feels a similarity between him and the lonely Iori, and the two of them begin to grow closer. Then, a "man" appears before the two of them.

Kishi Fumiya (Jiro) struggles to turn around the hot spring inn left to him by his late father. Meanwhile, Kishi's younger brother Toshiya (Eita Okuno) plots to start a new business by ingratiating himself with local influential figure Sakurai (Hirotaro Honda). The two have a deep-rooted feud over Kishi's ex-wife Akane (Saori), and the rift between Kishi and Toshiya deepens. In the midst of all this, a "man" appears before the two brother.

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"?