A large member of the Democratic Party of Japan (Mingo Yamada), rumored to be the next prime minister, is found dead in a toilet on an airplane. By chance, Zenigata and Kunikida, who were on the same plane, began an investigation into the murders from the situation at the scene and the murder weapon left behind. A man who had a connection with the assembly member surfaced while interviewing Morimoto (Keisuke Horibe), Hisada (Hiroshi Takahashi), Tamura (Seki Megmi) and Yoshimoto (Aoba Kawai) of CA. At the end of the day, a new murder case occurs on board.
