A certain tale of brothers. For home renovations, the second son Yasuhiro Yukino and his mother Natsumi Yukino are staying at the house of their real sister, Aunt Anna Machimura. Their cousin Tatsuo Machimura is borrowing a room in a university dormitory within Tokyo. However, they still can't quite relax because it's not their own home. Their mother also seems to be aware that she's living rent-free, so she diligently handles all the housework without taking a break... And while watching his mother like this, Yasuhiro noticed something... As did the eldest son, Yōhei... That their mother has an incredibly beautiful ass!!
