To the boys in her class, Mai Nanase seems more like a housewife than a high school student. Old-fashioned and frugal, she comes across as undatable to most. Mai is fine with her reputation though, as she is uninterested in the frivolousness of the relationships surrounding her.

This all changes when she meets her older brother's friend, Souta Nishino—a mature boy unlike the others she usually comes across. Both are inexperienced in love, but Nishino is captivated by Mai at first sight, and the two soon start dating. Thus begins a sweet love story about a couple who have never experienced their own, and their interactions with those who support them on this unfamiliar journey.