Ataru harbored uncontrollable feelings for Kaori, his stepmother. Though they were only related by marriage, he secretly loved her but could not express his emotions. To relieve his stress, he resorted to secretly filming her. One day, Ataru witnessed Kaori masturbating at home. Excited, he began recording her, intending to watch the footage in his room later. But everything changed when Kaori suddenly walked into his room and discovered him.