Yuta Yamayuchi, a high school student, instead of frolicking on the beach, spends the summer behind his textbooks. After all, there are exams on the nose! But Kei Higashida, his cousin, does literally whatever she wants with her brother. And what is the interest of girls, at her age? Of course, the contents of boys’ pants. Kay without any shyness studies the details of Utah’s anatomy, but, as a result of provocative fun, says goodbye to the virginity in his arms. Utah himself, happy with the opportunity to fulfill all his fantasies in reality, does not intend to miss a single opportunity to practice sex. After all, he has a girl who would not like to be disappointed by his ignorance in the intimate sphere of relationships.