Chu Zhaorong, the legitimate daughter of the Duke of Zhenguo, was sent to the palace to replace her sister as Emperor Zhaorong (hostage) due to the power struggle between her family and the royal family. However, she was thrown into the cold palace because of the emperor's disgust. In the cold palace, she learned the art of poison from her old nanny, and used poison as a blade to resolve crises such as the queen's frame-up and pressure from the queen mother, and was gradually promoted to the title of imperial concubine. At the same time, the regent Gu Jingheng, who holds military power, met her because he was investigating a conspiracy in the court. The two used each other to fall in love with each other, and worked together to put down chaos such as the queen's rebellion and the emperor's death. In the end, the heroine became the "behind-the-scenes decision-maker" with all the power in the six palaces, guarding the country together with the regent, and harvesting a happy love.
