For ten years, Dizang Palace’s deadliest assassin has been controlled by a poison called “Wuhuo.” Sent to kill the Crown Prince, she crosses paths with the Prince Regent, who is hunting the assassin. Her master then gives her one month to kill him. To survive, she poses as “Seventeen,” a concubine of the Crown Prince, and becomes the regent’s personal shadow guard. His constant tests give way to trust—and love. She steals the antidote, breaks free, and defeats the Palace Master with the regent’s help, becoming Dizang Palace’s new ruler. Just as peace seems within reach, the enemy who wiped out the Pei family returns to the capital.