Oikawa Tooru's twin sister, Oikawa Miko, has just transferred from the power house school, Shiratorizawa, to Karasuno. She meets a couple of third years who are the captain and co-captain of the boys' volleyball team. She watches one of their practices and ends up getting invited to their next practice match along with their training camp. How will Oikawa Tooru react when he sees his sister with one of his biggest enemy's team, his little kouhai Kageyama Tobio. And how will he react when he discovers exactly why she transferred from Shiratorizawa. (cover credit goes to the artist)