Female doctor Yun Wan was imprisoned because her master was falsely accused of poisoning, and she pursued the truth alone; she met Xiao Heng, a proton from the enemy country, in the imperial hospital, and Xiao Heng intervened in the investigation in the name of cooperation in exchange for freedom; the two discovered that the poison their master was poisoned came from a strange insect from the Western Regions, and was related to the palace. A prohibited object was found; the clue pointed to the Minister of War, Yun Wan sneaked into the mansion and found the secret room account book, recording the conspiracy during the late emperor's time; Xiao Heng's identity was suspected and was placed under house arrest. When Yun Wan rescued him, he exposed his medical and poison skills, and the two escaped; the Queen Mother sent a killer to kill him Yun Wan was poisoned to save Xiao Heng, and Xiao Heng introduced the poison with blood; the master woke up and told the truth: Xiao Heng was the orphan of the late emperor, and was secretly sent out during the coup ten years ago; Yun Wan assisted Xiao Heng in contacting the old troops, and at the same time healed the emperor who was controlled by the Queen Mother; In the end, the Queen Mother forced the palace, Xiao Heng revealed the secret edict of the late emperor, Yun Wan used a new antidote to solve the witchcraft; the emperor recovered, Xiao Heng gave up the throne and asked to leave; Yun Wan resigned and followed Xiao Heng to retreat to the south of the Yangtze River to practice medicine. Many years later, they both have children, and the past is like a storm.
