Haruka feels down when the boys start teasing her for her big breasts, even ranking her #1 in a 'biggest breasts' chart. She and Yako visit Nayu's house, where Nayu asks them to be models for a fitting session to gain awareness for the underwear club. Whilst Yako agrees, Haruka is a little worried about it. Nayu later tells them how she came to live with Keigo after her parents died. Haruka tells Yako about the boys' ranking, but says she will bear with it for Nayu's sake. Nayu manages to get permission to use an empty classroom after educating the teacher, Tamaki Mizuno, about her underwear. The session gets a great turnout and Haruka is surprised by the kind response to her modelling. Hiroki tries to stop some peeping toms, but both he and the girls end up getting lectured by Tsukamoto, saying the underwear club would never come to be. Afterwards, the girls stumble upon some underwear that even Nayu has never seen before, and are teased by another student, Kiyono Amahara.
小町の言葉にヒントを得た奈由は、正しい下着の着け方をアドバイスする説明会開催のため、弥子と遥に下着モデルをお願いする。
弥子は進んで協力を約束。一方、胸に負い目を持つ遥は、人前での下着姿に不安を覚える。
だが、両親を亡くしても明るく振舞う奈由を見て、勇気を奮ってモデルに挑戦する。
説明会は、開始前から大盛況。だが、奈由にモデルを頼まれた新任教師の水野環が、ノゾキを働く男子生徒を制止する小町と出くわしてしまい、大騒ぎになってしまい…
Haruka se siente deprimida cuando los niños comienzan a burlarse de ella por sus grandes pechos, incluso clasificando su número 1 en la tabla de 'pechos más grandes'. Ella y Yako visitan la casa de Nayu, donde Nayu les pide que sean modelos para una sesión adecuada para crear conciencia sobre el club de ropa interior. Mientras Yako está de acuerdo, Haruka está un poco preocupada por eso.
