The son was engaged in an affair with his stepmother, Ryouko. Their twisted love knew no bounds, driving them deeper into forbidden pleasure and sin. Keeping their secret, they took refuge in the home of Ryouko's sister, Natsumi. The son's desire was to witness his mother—his own stepmother—being physically embraced by another woman. The jealousy he felt as his beloved mother was loved and accepted by her own sister only intensified his arousal. Natsumi, accepting the son's desire, indulged in their twisted bond, pushing their relationship into even darker depths.