Toshiki Inaba is one of two protagonists in the narrative, a college student and childhood friend of Miyuki Serikawa, the tutor for the Sagayama family. Following the death of Chiyoko Sagayama's husband, he discovers a mysterious video showing a bound woman with an obscured face being violated. While unable to identify her visually, he instantly recognizes the voice as Chiyoko, the recent widow. This discovery fuels his plan to act on his lustful desires towards her.

His scheme extends beyond Chiyoko to target her daughter, Taeko Sagayama, and his friend Miyuki Serikawa. He approaches all three women under the guise of offering support during their grief. His true intention, however, is to exploit their vulnerable emotional states to establish inappropriate relationships with each of them. The narrative presents his actions as predatory, exploiting their circumstances solely for his personal gratification.

Throughout the described events, Toshiki Inaba's motivations remain consistently driven by lust and manipulation. The narrative does not depict significant character development or redemption arcs for him.