Murder Case in Deep Mountain Villa

While Keisuke Nogami and his daughter Misaki were on vacation in Karuizawa, a seemingly "perfect locked room suicide" case occurred in a neighbor's villa - the famous brain scientist Seiji Mitarai was shot to death in the study. The door was locked from the inside, there were no footprints in the snow outside the window, and the murder weapon disappeared. The police were eager to close the case with suicide, but Keisuke discovered three unexplained physical anomalies at the scene. As the investigation deepens, a serial imitation murder case spanning two decades comes to light, and the placement of each corpse accurately corresponds to the illustrations in a banned book in the 19th century. The murderer is challenging Keisuke - the truth of the case is more frightening than the murderer himself.