The sisters Rena (Reina) and Aina have both fallen for their stepbrother Shota (Shouta) and accepted his “training.” He indulges in perverted games with them anytime and anywhere, leading the sisters deeper into depravity and submission. However, tension arises when Aina receives a love letter from another boy, sparking Shota’s interest in a different woman. This threatens to disrupt their shared, taboo relationship as jealousy, possessiveness, and further corruption play out.
