Childhood friends Tomo Aizawa and Junichirou "Jun" Kubota do everything together, whether it be training or just enjoying a fun day out. Anyone would think that these two are best friends for life. The only issue is that the tomboyish Tomo is in love with Jun, but he regards her like a brother.

At the start of their first year of high school, Tomo confesses her feelings to Jun. However, her rough mannerisms and lack of hesitance to throw a punch do nothing to sway Jun's heart. Realizing that he will remain indifferent to her affections unless she does something about it, Tomo must find a way to knock some sense into Jun and open his eyes to what is right in front of him.