A story of incest between a mischievous sister 'Iroha' and her timid brother. The more she thinks 'There is an absolute line that must never be crossed,' the more excited and inflamed she becomes. She seduces her serious brother with outrageously lewd provocations, driving him to ruin!! His reason gradually crumbles, and in the end, he falls completely under the control of his 'little devil sister'...!?
