Riko Kohinata has never been particularly interested in romance. However, she doesn't make a big deal about it, unwilling to admit it to herself or others. One day, while studying at her classmate Tomoka's house, a young girl wearing a school backpack comes in! It turned out that Tomoka has a younger sister who's an elementary school student. Riko is so captivated by the cute little girl that time seems to stand still, but the younger sister reacts to Riko with hostility instead… A heartwarming story of a high school girl who loves children and an elementary school girl who wants to grow up. This age-gap girls' love comedy is about to begin! (Source: Kadokawa, translated)