Rekihiko Tokiya is an excellent detective in Kyoto. While he chases a suspect, Rekihiko Tokiya falls into a water storage pool at an abandoned factory. He wakes up in a hospital room. Rekihiko Tokiya is stunned that he cannot remember anything from the past 20 years. He is 51-years-old, but he cannot remember anything from the age of 31 when he started work as a detective. He is a divorcee, but he has does not remember his ex-wife.
Tomozo Sudo is a detective. Due to an incident, he is excluded from investigative work. He is then assigned to work in a division responsible for taking care of animals whose owners are suspects or missing. Keiko Usuki is a police constable and works in the same division. She loves animals more than humans. Keiko develops inferences from clues from animals left behind at crime scenes. Tomozo and Keiko work together to solve cases.