During questioning, Hikaru mentions the name "Fujisawa Ako." The detectives immediately begin investigating Ako's background. They become convinced that love is at the heart of this case. Ako, one of Ryuji's experimental subjects, was masturbating in the bamboo grove at her home. She remembers herself writhing in pain and pleasure with fishing line wrapped around her body and plays with her private parts. "Doctor, look! Ako is doing it right... aaah!" A series of spine-chilling experiments, and the closer they get to the heart of the case, the deeper the mystery becomes. It all started on that day, that moment, and that encounter!!