Hitomi was asked by her husband's friend to be her son's tutor. Hitomi, who has a personality that can't refuse when asked, teaches Koichi, who is currently in the second wave, to study, but Koichi only cares about Hitomi's breasts and doesn't concentrate on studying. He even starts saying he'll study if you let him touch his tits. Hitomi lets Koichi touch his chest, but the desire gradually escalates...
