Ning Heng, a modern toxicology researcher, crosses over to become the adopted daughter of the Ning family and marries the mad king Xie Zhaolin on behalf of her eldest sister, who is about to die soon. On the wedding day, she detected traces of chronic poisoning from the Xi Zhu and the late emperor's relics, pointing the finger at the powerful Empress Jiang. Xie Zhaolin went crazy to protect her, Cui Yuheng provided clues to the forged medical records, but Su Wanyue held the Ning family's account books that were enough to reverse the case. The couple teamed up to investigate the case, but found that behind the death of the late emperor, there was also a shocking deal involving the throne, bloodline and the world.
