Original title: 大悪司
In a parallel universe, feminist "Womenrica" (a group called WIME) won World War II, and forced a female-centric constitution upon the defeated Japan. Japanese city governments "outsource" the task of peacekeeping to local organizations, all lead by females.
Former juvenile delinquent, Yamamoto Akuji was one of the POW's who fought alongside Japan, only to end up having to become a prisoner of war for a year after losing against WIME.
Once he is released from prison, Akuji heads to his home for the first time in three years, the grand city of Osaka where he is heir to the largest gang called the Wakame Gumi, in which his grandfather, Yamamoto Ippatsu, who was a legend among others "properly" inherited after sleeping with the daughter of the former landlord many years ago.
While initially unhappy with how much the war has affected the cities setting, Akuji plans on visiting the love of his life, Haku Minka, and figures that she has grown to be a beautiful, and much more mature woman from the last time he saw her before being deployed to the war three years prior. As this warms his heart, he happily lingers to his home in hopes of having a celebration for his return.
Akuji's moments of relief due to his house being still in one piece gets cut short when he finds that one of his grandfather's former lovers, Ichihashi Ran, has become the new boss of the Wakame Gang. He gets informed that he is no longer allowed to stay within the household of the Wakame Gang due to his gender, and the fact that only women can be at the ruling position of factions, due to WIME winning the war and changing many laws. Akuji is also told that his father passed away during the war and that his grandfather was absent from Osaka for a large amount of time in order to find and battle someone more powerful than he was, meaning that there was no other decent choice but to make Ran the leader of the Wakame Gang. Akuji, angered by the fact he no longer has a place to reside in, attempts to fight back as Ran orders the gang's lackeys to subdue him. Thanks to having his body worn out from jail, Akuji loses the fight and is thrown out of his residence.
Akuji then shortly wakes up after only to become more infuriated, and takes out his frustration on an old drunkard bothering him, he gets stopped by the two Vice Leaders of the Youth Service Group, and is taken captive by them, Akuji then later manages to trick the both of them into liking him after lying about making his gang's most notable recipe, and instead treats them both to an amazing session.
Due to how easy it was for him to subdue the two Vice Leaders, Akuji plans on using the Youth Service Group to rebel against the Wakame Gang in hopes of retrieving his household back. He shortly afterwords sleeps with the main leader of the Youth Service Group and makes careful preparations. Thanks to his past grudges against WIME, who have most of the power in Osaka, and the stress with having to deal with a corrupt woman taking his household, Akuji takes it upon himself to dominate Osaka, so that the city can be in proper hands once more.
Soon after, his associates and personal trainers find word that Akuji has come back to Osaka, and end up joining the Youth Service Group to support Akuji, not only them, but a young girl who was a reserved, but powerful student by the name of Takega Satsu claiming to be Akuji's own aunt joins him as well.
With multiple territories, blood to be split, and the management of his slowly rising company on the line, will Akuji be able to fulfill his dream of conquering Osaka all the while maintaining a genuine relationship with the choice of one of five different women who can potentially become his wife in the future, all while having different types of fun with multiple other women at the same time?
It's a kill or be killed, high-stakes conquest as Akuji and his gang head straight to the top of Osaka!