Onee-san Ha no Ore ga Naze Chicchai Kimi wo Suki ni Natta no ka?

During spring break following his middle school graduation, Sky Toochika intervenes to rescue a tiny girl struggling to stay on her feet in a crowded train. Assuming she is merely an elementary school student, he thinks nothing more of the encounter—until he begins high school and discovers that same petite girl sitting right there in his classroom. Her name is Chito Naruse, and despite her small stature, she is breathtakingly beautiful with a seemingly boundless reserve of energy. To Toochika’s complete shock, this pint-sized classmate wastes no time confessing her feelings for him. The confession presents a unique dilemma: Toochika is entirely devoted to tall, older women, making a cute, undersized girl like Chito the exact opposite of his type. When he turns her down, she boldly declares that she will simply reshape his preferences to fit her, leaving him both bewildered and slightly terrified. Despite his initial resistance, the two soon begin spending time together as friends, and Toochika gradually finds himself seeing far more in Chito than just an adorable underclassman. This romantic comedy follows an older-women-loving boy and a determined, diminutive girl locked in a tug-of-war over matters of the heart, exploring how unexpected connections can challenge even the most firmly held ideals.