A certain tale of brothers. For the sake of home renovation, the second son, Yasuhiro Yagi, and his mother, Azusa Yagi, are staying at the house of their real sister, Aunt Yuuko Ishibashi. They are borrowing a room from their cousin Tatsuo Ishibashi, who lives alone in Tokyo while attending university. Their mother also seems to have the consciousness of being a guest, so she diligently handles the household chores without rest… And as Yasuhiro watches his mother, he finally realizes… Then, even the busy elite salaryman and eldest son, Yohei Yagi, notices… That his own mother has an incredibly beautiful ass！！
