In the 12th year of the Republic of China, although the Qing emperor had abdicated, the Forbidden City was still a small court with the emperor and his subjects. After Rong'er, a commoner girl, became a palace maid by accident, she formed a relationship with the guard Li Qi, and was favored by Puyi because of her intelligence and liveliness. Rong'er was appreciated by Aunt Shouxi for her understanding of cooking. Sun Yiren, the chief eunuch of the two palaces, had been stealing treasures from the palace for a long time and taking human lives lightly. After Rong'er learned about this, she investigated the theft case side by side with Li Qi. After several life and death, Sun Yiren was finally brought to justice, but the mastermind behind the scenes was still hiding in the dark. In the 13th year of the Republic of China, Feng Yuxiang's army drove the Qing Dynasty out of the Forbidden City. The mastermind behind the theft attempted to transfer the treasures in the palace to sell them to foreign merchants, but the conspiracy was discovered by Rong'er. Everyone joined forces to recover the national treasure and let the thief get the punishment he deserved. Rong'er, who left the Forbidden City, reopened a restaurant in Beijing and was known as the "last chef."