Popular quiz show champion Kenkichi Sendo (Toshoiaki Karasawa) is undefeated only thanks to the program staff helping him cheat before each game. When a weekly magazine reveals his secret, he attempts to look up the answers on his own in a panic. Costumer Numata (Hikaru Ijuin) discovers what Sendo is doing and a scuffle ensues leading to Numata's death. Furuhata suspects who killed the costumer in the locked room and decides to challenge the undefeated champion.
