Hitorijime - Choukyou Ganbou summary:

Mahiro's father has remarried and Mahiro is supposed to live with his new family including honor student Rei who is in the same class with him and believes "a guy who thinks of nothing but sex shouldn't be allowed to live together with her." Her words enrage Mahiro and he began to distance himself from her and on that moment, an unexpected reaction from Rei....?