Aspiring to be admitted to a good university and to become a lawyer, Tasiro Yuusuke, a tenth-grader from Kyushu, enrols in a prestigious high school in Tokyo. Plans are made for him to live in his uncle's house, part of which is rented out while his uncle is abroad on business. A realtor's mistakes leaves Tasiro sharing the house with Kei Yamaba, the most beautiful girl in the school, who is also his classmate. There is the risk that their unexpected 'co-habitation' will be discovered by the school authorities. While he grows increasingly attracted to her, he is often irritated by her innocent and nonchalant attitude towards their predicament.