大明洪武年间，丁武和蒋瑍是锦衣卫内一对亲如兄弟的小旗官，一个家有怀孕的老婆，困于茶米油盐；一个爱上了青楼女子，在平凡的职场中等一个上位的机会。两人奉命调查一桩连环杀人谜案，牵出一起重大贪腐案，紧要关头，线人被杀，线索屡屡中断，锦衣卫内藏有内鬼。丁武压力巨大，开始怀疑自己，也开始怀疑行踪诡秘的兄弟。

During the Hongwu period of the Ming Dynasty, Ding Wu and Jiang Huang were a pair of brothers in the Jingyiwei. One had a pregnant wife and was trapped in the tea, rice, oil and salt; the other fell in love with a woman in a youth house and was waiting for a chance to rise to the top in the ordinary workplace. The two are ordered to investigate a serial murder mystery case, leading to a major corruption case.

반역의 기운을 감지한 황제는 호위대 도찰사에게 수사를 지시하지만 계속되는 증인들의 죽음으로 미궁에 빠지게 된다. 한편 도찰사 내부의 첩자가 존재를 알게된 도찰사 '정무'와 '장환'은 최후의 전투를 준비한다.