Kuchibiru ni Uta wo: 15-nengo no Kimi e
くちびるに歌を～15年後の君へ～
Nazuna harbors a strong aversion to men after her father abandoned the family for another woman. She begins to think all boys are attracted to their attractive chorus teacher. Tension arises between her and her childhood friend Keisuke when he makes a comment about the teacher. Their friendship deteriorates, and the question remains whether they can mend their relationship.