Miku, Boku dake no Imouto.

One theory is that Sabao is a dull middle-aged man who works at a factory that smells like scent, which is rumored to be making parts for military equipment. I have no friends, and of course no lover. My only reason to live is my sister, Miku, who waits for him to come home every day. A gentle and cute, perfect sister, Miku. Sabao feels great happiness in living with her. However, the feelings for Miku, who was growing at the same time as happiness, were never forgiven by his brother and sister.