The emperor's grandson Li Ni, guards the border and is forced to take on the responsibility of quelling the rebellion. Although Li Ni is the grandson of the emperor, he was never loved by his father. He hides his identity and is content with being a carefree frontline border general who has no intention of fighting for power. During military campaigns against the rebels, he encounters the ambitious Cui Lin, who is the only daughter of General Cui Yi, the commander of the Cui family army. Cui Lin concealed her true identity and disguised herself as Lieutenant He, fighting alongside the army. They cross paths with each other many times on the battlefields. One is scheming and witty, the other is guileful and forthright. In their competitiveness with each other, from time to time they calculate and predict each other's plan and movement to fight as the winner which leads them down the path of falling in love.

Set in Shanghai in 1948. A traitor tells information about a high-level CCP undercover and Nationalist secret service tries to find him out.