To fulfill the desires of clients seeking sexual relationships with blood relatives, Hirokazu Takahashi devises a plan. A man who had found purpose in life by raising his sister after the death of their parents is devastated when she gets married. Desperate, the brother makes a new request: for her to pose as a model for a painter, who is actually the director in disguise. Though uncomfortable with the idea of nude sketching as a married woman, she cannot refuse her beloved brother's plea. Gradually, she gives in and surrenders her body. Later, she is summoned again to a hotel to model, this time blindfolded, under the pretense that a male model will also be present—unaware that it is her brother participating. Without realizing the truth, she engages in sexual intercourse with him, moaning in pleasure and losing herself in ecstasy. The scene unfolds with intense emotion and dramatic depth, going far beyond a mere assignment.