Thirteenth [Key]

In the winter of 1998, university mathematics teacher Gu Chuan received a will invitation from Wuling Villa. The owner of the manor, Ye Shenwu, passed away, leaving behind twelve keys and a strange rule: all twelve heirs must arrive and turn the keys at the same time to open the underground archives. After a snowstorm closed the mountain, the first body appeared in the archives room. The door is closed from the outside, the windows are missing, and the keys are still in everyone's hands. Everyone thought it was a perfect secret room, until Gu Chuan discovered that they had misunderstood the door from the beginning.