She has the looks of a model that stands out from the crowd, and on top of that, she has a great personality, too. Daily life with such a sister must seem quite strange to other people.......? This is a romantic comedy about a boy who will "definitely" get together with a cute little sister in the end!

(Source: ComicWalker, translated)

A beautiful older lady regularly visits a coffee-shop where the high school student Hayasegawa-kun works at. He doesn't know her name, her job, or where she lives, but she is nevertheless his "ideal woman".