Eccentric and blunt, the walrus Hiroshi Odokawa lives a relatively normal life. He drives a taxi for a living, and there he meets several unique individuals: the jobless Taichi Kabasawa who is dead-set on going viral, the mysterious nurse Miho Shirakawa, the struggling comedic duo "Homo Sapiens," and Dobu, a well-known delinquent. But Odokawa's simple way of life is about to be turned upside down. The case of a missing girl the police have been tracking leads back to him, and now both the yakuza and a duo of corrupt cops are on his tail.

October 4 marks the fateful day when a high school girl vanished, triggering an unpredictable series of events. In order to unravel the mystery behind the girl's disappearance, all of the key witnesses connected to the case recount the events leading up to and following the crime. As the pieces to the story come together, they all seem to be connected to one individual—taxi driver Hiroshi Odokawa.