Mo Chenghui is a professional technician of the No. 7 Criminal Police Brigade of Daicheng. On the surface, he is a good human citizen, but what he carries in his mortal body is the beast soul of a demon king from another world. During a strange large-scale serial murder case, he met a female college student named Bai Zhilan. When the serial murderer committed his first crime, he was involved in it and was rescued by the mysterious second personality in his body. Mo Chenghui also realized that Bai Zhilan was not an ordinary person. The best proof was that the beast soul of Shuangshu, the seventh general under the Demon King, resided in her body. The strange serial murders, the powerful energy that does not belong to this world, is there something that is already destined? !