In the previous life, low-ranking female official Su Wantang was poisoned and killed by the queen in the cold palace because she appealed for the framed Concubine Duan. On the verge of death, she witnessed the third prince Xiao Chengjin, whom she regarded as her brother, personally crush the love note she had hidden for ten years. Reborn at the age of 18, Su Watang used his "stupidity" as a shell and relied on the memories of his previous life to work step by step: first, he broke the secret communication scheme between his sister-in-law and the foreign ministers, and then solved the poisonous frame-up scheme at the Queen Mother's birthday banquet. In the undercurrent of the harem, he also uncovered the intricacies of the case of Concubine Duan and the murder case of Xiao Chengjin's mother's family. But the gloomy prince who once made her feel discouraged came into play by "coincidence" again and again when she turned the tables - he blocked the assassin's poisoned knife for her, hid her in his dragon robe and said, "I'll guard you this time", and on the night when she exposed the queen's crime, he was red-faced. He handed the blood-stained love note to her: "The one I burned back then was fake." In the entanglement of sadomasochism, the two worked together to overturn a twenty-year conspiracy. However, when the truth was revealed, they had to face the fate of "you and I have the same blood feud."
