Hiroki Yoshihara (Ryohei Abe), the president of Kyoto Rescue Service (KRS), a venture company specializing in disaster prevention such as distribution of disaster and weather information and operation of evacuation shelters, was found dead in a mountain stream. On the night of the incident, a torrential rain occurred in Kyoto city. Yoshiwara was thought to have been attacked by someone while searching for climbers in the downpour.
Satoshi Itomura (Takaya Kamikawa) who was present notices that a whistle is wrapped around Yoshiwara's wrist. It was a 'rescue whistle' to call for help in the event of a disaster, but Itomura discovered that Yoshiwara had further lowered the old whistle from his neck. Yoshihara wonders why he carried two whistles with him.
The man Yoshihara was looking for is still missing, and members of the 'Special Investigation Countermeasures Office' such as Rio Kanzaki (Chiaki Kuriyama) suspect his crime and start an investigation ...
Eventually, KRS vice president Hoshi Vegetable Beauty (Aimi Satsukawa) and university student Keita Gojo (Gaku Oshida) who was present at the evacuation center also emerged on the investigation line. What is the unexpected truth of the incident that Itomura derived from an old whistle?