Gu Qingxue constantly causes trouble to rebel against the fate of becoming the heir arranged by her grandfather. Gu Yuan hires Lu Ting, a retired soldier king, to be her bodyguard. Gu Qingxue makes things difficult for him at every turn, but Lu Ting counters every move with overwhelming force. Her second uncle, Gu Jianguo, conspires with the overseas assassin organization "Black Snake" to carry out repeated assassination attempts. Lu Ting happens to be Black Snake's sworn enemy. The two go from distrusting each other to fighting side by side. Gu Qingxue matures, reclaims control of the group, and falls in love with him. Haunted by past trauma, Lu Ting chooses to leave, but at the airport, Gu Qingxue publicly confesses her love and begs him to stay. In the end, the two each head toward their own battlefield, promising to be each other's armor and protector.