The private detective, known as ‘Cat’, is a lazy, good-for-nothing father to his son, Taku. One day, Washio, a gangster who has come to ransack the shop where Taku works, recruits him. Taku begins working under Washio but, having doubts about his methods, returns to his former life. Washio and his gang then plot revenge against Taku, the traitor, and Cat, with whom they have a long-standing feud.