A fire in a building in the old city leaves one person dead. Behind the seemingly ordinary incident lies something more. During a routine examination of the scene, Xing Kuan, captain of the criminal investigation team, spots something suspicious. But the clues he uncovers do not bring the case to a close. Instead, they lead to an even greater mystery. Trouble is brewing in Yancheng, and an investigation team from the provincial department arrives to look into the case. Xing Kuan receives an anonymous letter, and a photograph brings an old lead back to life. Can this tangled case finally be solved? After breaking through the dense fog, Xing Kuan finds an even greater challenge awaiting him...