In the closet of her new apartment, Kae finds a notebook left behind by a previous tenant, Mano Ibuki-sensei. It's Ibuki's diary record of her early elementary school teaching career. The notebook enthralls Kae, who also hopes to become an elementary school teacher. Kae fills up her time with her studies, her mandolin playing, and working part-time at a stationary store, but she misses her best friend Hana, who is studying abroad.

To make matters worse, Hana's boyfriend, Kashima, seems to be trying to flirt with Kae in Hana's absence. Kae has no desire to betray her friend, and she is actually more interested in a dark-haired artist, Ishitobi, that she finds herself constantly running into. Kae finds comfort, inspiration, and new insight through reading the forgotten notebook of Ibuki-sensei.