High school girl Mio Omori comes from a poor background. Life is hard enough for Mio, whose mother, an ailing widow, is getting treatment at a hospital. With the younger brother, Hinata, being a school student, Mio has to work part-time jobs to support her family. Her life gets even more complicated when a rough young man, Shoei Jinnai, throws money at her and steals her first kiss, claiming to have bought her.

Yokujou Climax is a romance that showcases the love-hate relationship between Mio and Shoei. Mio realizes that there's more to the guy than it seems, and gains new insight about her own and other people's lives.