One day, Iwao Takemura, a detective at the Nagano Prefectural Police Iida Station, discovers a part of a dismembered corpse at the Matsukawa Dam where he went fishing. At the Iida station, the search for the rest of the corpse began, and Takemura, who became the first discoverer of the dismembered murder, immediately investigated with his subordinate Katsuragi, and with his wife Yoko, made a deduction similar to "Columbo".