Takuya is a high school graduate who is preparing for another chance to enter a university. One day, his parents suddenly go travelling. To take care of him, the Kasugai sisters, Urumi and Manami, come to his house. He is happy to meet them again, but they don't do anything.... But days later, they offer him to be his tutors. They first give him some test, but his scores are terrible.... Takuya says to Urumi, "If I get good scores at the next practice examination, please go dating with me." She says yes and Takuya successfully gets good scores. He continues to study hard with two attractive girls. Well, will he be able to concentrate on his study...?