In the bustling entertainment district of Asakusa Rokku in Tokyo, Gen Shimura is a local celebrity known as the Fighting Festival Gen. He helps run his family's strip theater, the England Theater, and spends his days with his three closest friends: Makoto, a rickshaw puller; Jimmy, a part-time worker; and Mattsun, a dim-witted monk. Their peaceful if chaotic life is disrupted when Gen falls for Kyoko, a worker at a local takoyaki shop. At the same time, a series of violent, seemingly random attacks begins plaguing the neighborhood, carried out by assailants wearing monkey masks.

As Gen and his friends investigate these incidents, they discover a deeper conspiracy tied to the redevelopment plans proposed by a local politician, Toranosuke Tono. The fight to protect their beloved Asakusa from greedy developers and criminals becomes personal when it draws in Gen's childhood friends, the金山 brothers. The older brother, Ryuta, is a real estate agent whose company is facilitating the redevelopment, while the younger brother, Raita, leads a dangerous semi-organized criminal gang. The series follows the group as they confront these threats, defend local businesses like the girls' bar Lupinus run by Mama Akina, and face dilemmas that test whether their bonds of loyalty can survive pressure from both the yakuza and outside forces trying to tear their community apart.