One dark and snowy night, after the Sui dynasty has come into power, a convoy sent by the Kingdom of Khotan is ambushed and massacred. Not a living victim remains–and the attackers, along with a chest holding precious treasure in tribute, have vanished. A member of Emperor Yang Jian's secret intelligence agency, the Jiejian Bureau, pursues the case: the highly successful chief Feng Xiao. Feng Xiao's investigations take him to Liugong City, where all the top martial powers across the land are coming to meet. But another intelligence agency, the Zuoyue Bureau, has business in the same city–and they have sent Cui Buqu, an ailing but brilliant man who rivals Feng Xiao. These two equally proud men immediately clash and begin a battle of wits, only to hit a dead end on the increasingly cold case. Is the answer to this mystery out of reach, or can Feng Xiao and Cui Buqu find a way to the truth?