"If you blush, you lose." Living by this principle, the middle schooler Nishikata gets constantly made fun of by his seat neighbor Takagi-san. With his pride shattered to pieces, he vows to turn the tables and get back at her some day. And so, he attempts to tease her day after day, only to find himself victim to Takagi-san's ridicule again sooner than later. Will he be able to make Takagi-san blush from embarrassment even once in the end?

Takagi and Nishikata are in their final year of middle school, and have both anxiety and hope for the future. During the summer of their final year, on the day before summer vacation starts, the two find a kitten that they name Hana. They decide to take care of the kitten themselves until they can find its mother.

Takagi loves playing good-natured pranks on her classmate Nishikata. But try as he might, he can never prank her back — she's just too clever!

On a pretty, placid little island in the Japanese countryside, Nishikita teaches physical education at the high school he himself attended. The man is hardly an agent of change. He knows his place in the order of things and is careful not to rock the boat, perhaps even a little too much. When he receives a call from a former classmate Takagi, announcing her return, a flash of emotion strikes him. Takagi was Nishikita's best friend and unrequited first love, who had suddenly moved to Paris 10 years earlier to study. At the time, Takagi was constantly teasing him to shake him out of his torpor, and he notices that her attitude hasn't changed in the slightest when they are reunited. In fact, while in France she has only improved in the art of the retort, and Nishikita is still as bad at it as ever. He'll have to get used to it, though, as the new teacher he'll have to train is none other than the beautiful Takagi.