This book revolves around a group of seemingly unrelated modern urbanites, intertwined in a space of mysterious deaths, mental disorders, confusion and abstraction from reality. They were attracted by a legend called "Lightless Realm" and gradually embarked on a series of nightmarish journeys of investigation and self-rescue. Disappearances, madness, and suicide cases occur frequently. Everyone is looking for the truth, but gradually discover that their reality has been quietly eroded by a hidden world - the 'realm behind the door'. Some are victims tortured by memories, some are investigators trying to solve the mystery, and some are bystanders hiding in the shadows. There are many parallel lines and many mysteries. These people influence each other and reincarnate. As the truth is gradually revealed, human nature and malice, crime and punishment also slowly emerge. The book finally ends in the "Lightless Realm" where the three lines converge and start the ultimate showdown.
