Kyosuke Kozu (Masaomi Kondo), a university professor and a famous detective, is a big magic lover. He was asked to judge the Magic Competition to be held in Ito, and set out with his sister Nobuko, her lover's newspaper reporter Kenzo, and the brothers Shiro Kishibe. On the day, Shigeko Mizutani, who was supposed to play the guillotine technique, went missing, and she was found dead while her sister Yoshiko was taking her place. The suspects include Yoshiko, Shigeko's husband, Ryohei Mizutani, and her secretary, Yuriko.