Ye Ling Shuang and Qi Hai Rui are close friends who grew up together in the grasslands of Ye Bei. Although Ye Ling Shuang was regarded as an outsider of the grasslands and hated by her fellow tribe mates, the seventh princess of Ye Bei, Qi Hai Rui never looked down on her and treated her as her close friend. Ye Ling Shuang decides to pledge her loyalty to the princess for life.
In order to attack and conquer Ye Bei, Emperor Gao of Chao Kingdom designed a plot where he requested for Qi Hai Rui's hand in marriage. He was sure that Qi Hai Rui would reject the marriage proposal, and he would thus use this as an excuse to incite war. In order to save her kingdom and people, Qi Hai Rui decides to commit suicide by jumping down a cliff. Seeing her close friend die and the Ye Bei Kingdom fall apart, Ye Ling Shuang vows to seek revenge and takes on a new identity as Bai Lu to sneak into the palace in an attempt to assassinate Emperor Gao.
