Haruo Sugimura is fresh from serving a two-year stint in prison for assaulting someone when he is recruited by a loan shark named Sakai to help collect money for a company called Minami Hachi Ban Kogyo, baesd in Osaka. Their rates are ruthless: 10% interest is added every 10 days. Their customers are desperate: a hostess who owes money to other loan sharks, a man made suicidal because his family don’t love him anymore. Haruo learns about the art of the loan shark as well as the dark side of peoples personalities.