うさん臭い工場に勤務する冴えない中年男・サバオの唯一の生きがいは、毎日彼の帰宅を家で待つ妹のミクだけ。そんな彼女との暮らしに大きな幸せを感じるが、同時に膨らみ続けるミクへの思い、それは決して兄妹には許されないものだった。常に爆発寸前の情欲を何とか抑え込み、ギリギリのところで踏みとどまるサバオ。ところが、ある休日、海に出かけた2人はふとしたきっかけで遂に一線を越えてしまう。それは、予想もできない悲劇と喜劇のほんの始まりにすぎなかった…。

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.