We live in a society with declining birthrate where great extermination is respected and cuckolding is recommended if you want to impregnate someone. The protagonist's five friends kept boasting about their lower bodies, and as a result, the protagonist lost confidence in himself and lived a humble life. However, one day, one of his friend's mothers saw his cock and she discovered that he was actually one of the world's biggest exterminators! The protagonist, who has found his own self, seduces the beautiful women he always admired - the mothers of her five friends, each with a different type of beauty, one after another. In this way, he begins a harem life where he can impregnate his friend's mother and release his pent-up feelings.