Iroha Natsume (Miyuki) is the daughter of a rich man (Ozawa Tohru), who live together with a butler.
One day, Iroha she lent her clothes to Shiori (the daughter of the Butler) who gets kidnapped instead in the confusion and the kidnappers ask for a 3 million ransom to the family.
The father of Iroha (Ozawa Tohru), gets greedy and pays the ransom in counterfeit money. But that doesn’t work out and Shiori gets killed.
This causes great resentment in the butler and he holds a grudge.
1 year later Iroha gets kidnapped by a gang of traffickers and she is thrown into a dungeon. Covered with a mask, sinful incest acts happen.