Kyosuke (Masaomi Kondo) and his sister Nobuko (Yoko Moriguchi) were invited to the 10th anniversary party of the travel agency "Pigeon". At that seat, Ayako, the younger sister of President Gentaro, is shot dead. Other venues included Gentaro's brother-in-law, Palau branch manager Kiriyama, secretary manager Anna, and Miyo, who runs a restaurant on Palau Island. A few days later, Nobuko goes on a trip to Palau. She is kidnapped by someone in the field, and Kyosuke and other related parties rush to her. In Palau, there was Toshinosuke, the founder of Pigeon and retired. He was once a detective called "Sakuradamon Demon", but was accused of being arrested 15 years ago and was ousted from the Metropolitan Police Department. It was Kyosuke who proved his innocence.