15-year-old country girl, Suzume Yosano, has to move to Tokyo to live with her uncle due to her father's transfer. She bumps into a mysterious man who ends up taking her to her uncle's place after she gets lost. Turns out, Suzume will be seeing him a lot more often once she starts school because... he's her homeroom teacher!?

Included in the manga is a oneshot story called Tsuyu Kaoru (A Love Story in Moist Rainy Days) in volume six:
A romantic and melancholic love story behind a red umbrella.