In the summer of 2015 in Tokyo, Japan. Ryoichi dreamed of becoming a punk rocker when he was younger but became a timid salaryman at a musical instrument parts company. He has feelings for her, but he can't tell her how he feels..
One day, he has a fateful meeting with a turtle on the rooftop of a department store. He names the turtle Pikadon and he adores it, but his co-workers laugh at him. Ryoichi throws Pikadon into the toilet. He regrets what he did. The turtle though goes through sewerage and meets an old man who lives underground. Something then happens.
Detective Tono Kazuyuki (Sato Koichi) of the Tokyo Metropolitan Police's First Investigative Division resigns to take responsibility. However, he gets an appointment letter which he is unprepared for...to become an instructor at the police academy!
It is a useless role in the classroom involving theories about the many violent criminals. Tono, who has thus far used seemingly unorthodox measures to arrest criminals in investigations he obssessed over, assesses better than anyone else that he is least suited to be an instructor ... ... Awaiting him at the police academy he goes to as a new instructor are the naive young people of today who are attracted by the stability of being a civil servant and the cool uniform, particularly the trainee, Miyata Eiji (Miura Haruma), who handles everything tactfully. He is smart, good at sports and popular with both genders, but he has neither encountered hardships nor setbacks, and has nimbly made his way through an innocuous life. In fact, Miyata's way of life is far from the qualities of a police officer who protects the lives and possessions of citizens.