Natsumi is a teacher in her mid-twenties, but for Tomonori, she is unfortunately already engaged. Despite his preference for older women, Tomonori has fallen in love with Natsumi, his teacher.
In the anime, Natsumi occasionally gets inadvertently entangled in the various schemes and plots that the main characters devise against each other. At one point, she even attempted to have sex with Tomonori, but the effects of a drug she had taken wore off before anything could happen.
She is known for her kind-hearted nature and can be quite dense when it comes to matters of romance. Natsumi cares deeply for all her students and is very self-conscious about her teaching abilities.
