The second-generation president and his brother-in-law of the Toba clan, a don of the music world, are kidnapped. Singer Chiaki and pianist Yonosuke contact Chiaki's father, a detective, and police surround the island. The president's mother-in-law, who entered the island with the ransom money, is shot and injured, but the culprit who stole the money cannot be found. Chiaki begins to investigate the island on her own, and soon finds Kunihiko's body, a hunting rifle, and the ransom money in an island bomb shelter. This is a mystery that challenges the mystery of a bizarre kidnapping and murder involving the family of a prestigious president