A private record depicting the sexual development of a teacher and his student Mao, filmed in an empty classroom after school. Since Mao's enrollment, the teacher has taken a special interest in her, quietly observing her growth each day. Their relationship gradually deepens into something more intimate, as the teacher begins secretly documenting their sexual encounters. Capturing Mao's transformation through a video camera, he continues filming in quiet, secluded moments. This is a record where the teacher's personal desires intertwine with the girl's evolving body and emotions.