Mogura no Uta

Reiji Kikukawa is a young and impulsive police officer who follows his own guidelines. Therefore, when his personal beliefs about performing his duties come to light, it comes as no surprise when he is eventually dismissed. However, unbeknownst to others, he is assigned to go undercover to penetrate a perilous yakuza faction, the Sukiya organization, in order to gather proof to apprehend its leader, Shuho Todoroki.