Due to an influx of sinners, the Ten Kings of Hell were granted heirs to support them in the future. The said ten heirs studied together since they were children and were now all grown up. A collection of stories on relationships among them: "Enma's Studies": Enma has always aced his studies, but their recent lesson about 'Eros' leaves him confused, so he asks the frivolous Sotei for help. "Byodo's Unfair Romance in All Fairness": Byodo has always liked Godo since they were children, but the latter has feelings for their other mutual heir, Toshi. Heartbroken, Byodo vents his feelings out to Taizan. "Shinko's Dilemma": Being the heir to the first seat has been a struggle for Shinko, who was known for his gentle nature, contradicting the imposing image of his father. One day, he meets the mysterious 'Blackhat,' to which he can't help but be drawn. お父さんは閻魔王！この恋、ぜったいに秘密です！ 冥界で死者の罪を裁く10人の王さま・十王。 その十王をそれぞれ父に持つ息子たちは、二代目王を継ぐべく日々修業中！ 閻魔王の堅物息子・閻魔は、宋帝王の飄々息子・宋帝にいつもからかわれてイライラがとまらない！ ある日、人間の性愛を学ぶ授業で、試験に落第してしまった閻魔は、やむなく宋帝に助けを求めるが、宋帝から「性愛は実習しなければわからない」と言われてしまい?! 10人そろってお年頃”地獄の王子様”たちの十人十色な恋模様！