Aki enters his room, and is met by a woman who is changing clothes. She turns out to be Ayaka's sister Nana, who teases Aki by proposing to undress, calling him feminine, and trying to check if he really has a penis. Nana stays over the summer, and they become closer after sharing a bed and playing video games together. At the public swimming pool, Nana's friends Maiko and Mea spend the day flirting with Aki while calling him feminine. Nana challenges Ayaka to a swimming competition, where the winner gets to do anything they want with Aki. As they are equally fast, the pool closes before a winner is determined.