The mother fell ill and was hospitalized, so the daughter Shinjo came back to her parents' home to help with housework. While chatting with her father, her younger brother returned but seemed distant. Curious, Shinjo peeked into his room and discovered he had bought an onahole. Realizing he was a virgin from his cluelessness, she teasingly provoked him, only to be pushed down by the strength of his pubescent hormones… From that day forward, she was subjected to her brother's sexual desires…
