High school student Mio Omori hails from a disadvantaged background. Life is already difficult for Mio, whose mother, a sick widow, is receiving treatment at a hospital. With her younger brother, Hinata, also attending school, Mio must take on part-time jobs to support her family. Her situation becomes even more complicated when a rough young man, Shoei Jinnai, throws money at her and steals her first kiss, claiming he has bought her. Yokujou Climax is a romance that depicts the love-hate relationship between Mio and Shoei. Mio realizes that there is more to the guy than meets the eye, and gains new insight into her own life and the lives of others.