Boku x (Onee Mafia + Ninkyou Yakuza)

Shizuku, a 5th grade elementary school student who has to live away from his mother due to family circumstances. He was supposed to live with his grandparents, but the people who came to pick him up were his mother's younger brother, Kasumi, and two mysterious foreigners. When I get home, I find myself in an unknown world, at the home of a very brave yakuza! ? A new life begins for them and Shizuku, whose relationship is unknown!