Detective Zero.

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.