Rino, now a stepmother after marriage, finds her stepson suffering under her husband's harsh treatment, accumulating daily stress with no outlet. The boy, repeatedly insulted as worthless and not their real child, harbors deep resentment. One day, he finally reaches his breaking point and rapes Rino. The traumatic incident shatters her mentally, sparking an emotional attachment to her stepson, gradually leading her to be completely dominated by him, body and mind.