High school student Natsuo is hopelessly in love with his cheerful and popular teacher Hina. One day at a party, he meets a troubled girl named Rui, and this encounter leads to a night in bed. After a while, Natsuo's father announces that he is getting remarried. The woman he is going to marry has two daughters. And it turns out that these two daughters are none other than Hina and Rui! Natsuo's shocking new life begins!
