Ichiban Kasuga, a low-ranking grunt of a low-ranking yakuza family in Tokyo, faces an 18-year prison sentence after taking the fall for a crime he didn't commit. Never losing faith, he loyally serves his time and returns to society to discover that no one was waiting for him on the outside, and his clan has been destroyed by the man he respected most. Confused and alone, he embarks on a mission to discover the truth behind his family's betrayal and take his life back, becoming an unlikely hero for the city's outcasts on his journey.