Natusmi is a teacher in her early to mid twenties, but unfortunately for Tomonori, Natsumi is engaged to be married. Tomonori loves older women and Natusmi (his teacher) is the girl he is in love with.

In the anime, Natsumi sometimes accidentally gets involved in some of the back-handed schemes that the main characters are doing to each other, and one time, tried to have sex with Tomonori, but the effects of the drug wore off before anything could happen.

She is a kind woman and is thick-headed when it comes to romance. She cares for all of her students and when it comes to teaching, she is very self-conscious.