[DeepL Translation - needs review] Volume 1 Introduction: Eight passengers on a train bound for a hot spring resort town in the mountains have been vaporized. A middle-aged police inspector tackles an unprecedentedly difficult case and runs into a college girl who is a maniac for deductions everywhere he goes. The middle-aged police inspector, who had been annoyed at the girl for interfering with his investigation, is now annoyed by this beautiful woman. The two become a great duo before lon...
