Mitsura is one of four male students at Nankai Academy investigating the murder of their teacher, Professor Yuko. He participates in the group's covert activities, which involve planting hidden video cameras throughout the school to collect evidence and target suspects identified in Yuko's planner. These methods include confrontations and sexual coercion against female students linked to the case.

Mitsura specifically joins Masayoshi in confronting Kiyoka Enjyoji at her estate, where they compel her to remove her uniform, exposing revealing undergarments, before administering punishment. This act aligns with the group's broader pattern of employing sexual coercion against female suspects during their investigation.

As the investigation intensifies, Mitsura continues participating alongside the others. Their collective actions grow increasingly driven by dark desires while pursuing the truth behind Yuko's death.