Ryotsu Kankichi, nicknamed Ryo-san, is a senior patrol officer working at the Kamearikoen-mae police box at Katsushika. Because of his daring, hearty, unconventional, haughty and overbearing personality, he is called "letter of apology Ryo-san" and everything he does is nonsense. There is endless trouble wherever Ryo-san goes. He makes Akimoto Catherine Reiko and Nakagawa Keiichi, his juniors from the same police box, fearful. His superior, Ohara-buchou, lives each day as if lightning will strike as a fearless power keeps going off day after day. He definitely doesn't have poor ability as a "patrolman of the police box" in the mediation of quarrels, taking care of New Year's gifts or discussion of neighbourhood problems but he has a bad temper, gets tired of things easily and detests working. He is a police officer but because he loves gambling, he spends his money recklessly and in addition to this mess, is heavily in debt. He has a weakness for get rich quick schemes, and has a manic desire and knowledge to have fun and make money. Then one day, Ryo-san receives a tempting proposition...
