Yajima Kintarou was once the infamous boss of the Hasshu League biker gang, who at their peak boasted more than 10,000 members, but after meeting and falling in love with a partially sighted girl named Akemi, he gradually mellowed and disassociated himself with gang life.

Unfortunately their love proved to be short lived when Akemi died in childbirth, but her last wish was that Kintaro would become a salaryman and raise their son, Ryuta in a stable environment. It's a request Kintaro cannot refuse, and after saving the life of the CEO of Yamamoto Construction he finally gets an opportunity to change his lifestyle once and for all. However, it seems the life of a salaryman is anything but stable when your employers are a multi-million pound constructor whose managing board is made up of corrupt ex-governmental ministers that are busy setting plans in motion to stage a hostile takeover and seize the company for their own nefarious dealings.