There are mutants who believe that they are empowered by God and refuse to co-exists with humans. After being defeated and driven away, the mutants known as "The Borderline" lived in exile. Zhao Yun Lan, a human, falls into a deep slumber to save Shen Wei, a mutant. In return, Shen Wei fulfills his promise to Zhao Yun Lan to be the keeper of the boundary. The humans create the Special Investigation Division (SID) to catch mutants who escape exile and bring them back to the border. After a million years, both sides were able to live peacefully and the Special Investigation Division became irrelevant and forgotten altogether, that is until a series of weird events begin to occur. Shen Wei joins the Special Investigation Division and realizes that Zhao Yun Lan is awake and knows nothing about their past. The Special Investigation Division also comes to realize that Shen Wei is no ordinary professor and somehow linked to the mysterious "four sages".