Tobi Sentō (Takashi Sorimachi) showed the “HIDE&SEEK” file to Fuwa Satoshi (Haruka Sugino).This file records the truth of unresolved incidents and was once held by Yuki Renko (Shiraishi Mai)'s father, Shinichi (Hirayama Yusuke) before he was killed.

Qian Shou told Riji: “The unsolved events recorded in this file are intentionally unresolved.It is our mission to bring these truths into the light.”Subsequently, Senju made the assassination of the deputy prime minister eleven years ago the next target of investigation and sent an information email to Okura.

This case occurred when Senju, Washizawa Taizo (Ukaji Goji), Kasaki Hideo (Nakamura Shunsuke) and others were still forcibly committing crimes. At that time, Nagakura Takaya (Otake Akihiro) was actively promoting the revision of the law.) while having dinner with the Prime Minister at a restaurant in Tokyo.

During the banquet, the deputy prime minister took medicine to treat chronic diseases handed over by his son Kaichi (Minawa Yuta), who was his secretary. He suddenly suffered from severe pain and eventually died.The cause of death was cyanide poisoning.Although Huiyi denied the suspicion, he could not bear the criticism from society and chose to commit suicide one month after the incident.