Die Mädels beschließen, alle eine andere Art kleine Schwester zu spielen, um Yuu bei seinem Spezialtraining zu unterstützen.
In order to prevent the novel's heroine from being revised, Yuu must perfect his love of little sister moe. Yuu and Suzuka both attend Sakura's radio program as guests, and Yuu begins flirting with Suzuka while on air as part of his training to become moe for little sisters, but...
Toutes les filles vont jouer chacune leur tour le rôle de la petite sœur de Yû dans un parc d'attractions.
原作の改変を阻止するためには、妹萌えを極めなければならない。祐は桜のラジオ番組に涼花とゲスト出演し、妹萌えの特訓として涼花とイチャイチャしはじめるのだが……。
Depois de ter ouvido que não compreende o moe de irmãzinhas, é decidido que Yu fará um treinamento intensivo para entender melhor sobre o tema.