Liu Yunuo is the pampered legitimate daughter of a general's household. Skilled in both the literary and martial arts, she gets her wish and marries the man she loves, the Third Prince Qi Xingyu. But after marrying him, she becomes his tool for killing, helping him remove every obstacle on his path to the throne. To outsiders, the couple seem deeply devoted to each other, but Qi Xingyu sees her as nothing more than a killing tool. Is she the dignified and gentle Third Princess Consort seen in public, or the assassin who spills blood in the shadows? Which one is the real her?