Shanghai Puzzle

On December 19, 1994, Shanghai police responded to a call at the famous Obsidian Mansion. A peculiar black structure purchased by businessman Gu Yunhui to fulfill a promise to his little son — to live in a fairytale castle. The house was filled with a suffocating scent of perfume. The owner's room had been hastily painted red. But the main thing — five corpses on the floor. Before the eyes of the police, Gu Yunhui, in a bloodstained robe, locked himself in his room and… vanished. And five minutes later, he was caught… five kilometers from the crime scene. Despite the impossible nature of his escape, Gu Yunhui was deemed guilty and placed in a psychiatric clinic, where he took his own life.

Twenty years later, his son invites a group of experts to the mansion. A psychiatrist, a forensic psychologist, an illusionist, a physicist, and a detective captain gather here to re-investigate this mysterious mass murder. Along with them is the brilliant eccentric mathematician Chen Jue, who has repeatedly proven that mathematical methods are quite effective in solving crimes. He is convinced that the key to the riddle lies in the strange magical tale that Gu Yunhui wrote before his death…