In the year 1936, a new party member accidentally discovers secret information that triggers the Xi'an Incident, thus beginning a story of infighting and schemes. When he was young, Wu Zhongming (Wang Xuebing) was separated from his older brother Wu Boying by kidnappers. He joins the Communist party later on and gets captured during one of his missions. His older brother tries to rescue him but dies in his stead. This happens during a time before the Xi'an Incident and the city has turned into a crucial place for vital intel. To win the final victory, the Communist party sends Wu Zhongming to go undercover as his twin brother Wu Boying and infiltrate the Kuomintang.