The protagonist is a girl known as Ume-chan, a nickname derived from her last name, Umehara. Her actual first name is kept a secret as it's both humorous and surprising. Ume-chan is secretly in love with a boy in her class named ISEZAKI-kun, but he's already in a relationship with a seemingly perfect girl. Ume-chan spends her time observing Isezaki from one seat behind and writing about him in a notebook. However, when Isezaki forgets his notebook and borrows Ume-chan's notes, she accidentally hands him the wrong notebook containing her thoughts about him. Mortified, Ume-chan is embarrassed when Isezaki reads it but is surprised when he takes it well and decides to be friends with her.
Although Ume-chan is pleased to speak to Isezaki, it's bittersweet as he still has a girlfriend. However, when Isezaki breaks up with his girlfriend, Ume-chan sees it as a chance to confess her feelings and hope for a relationship with him. Will Isezaki return her feelings?
