Yun Zhiyi, a modern toxicology researcher, transmigrates into a merchant's daughter who is humiliated and rejected by the Marquis Manor, and is accused of poisoning right as she wakes up. Relying on her poison-testing skills, she reverses the situation in public, turning the engagement annulment banquet into a humiliating banquet for the Marquis Manor, which also catches the attention of Pei Yanzhou, the Junior Magistrate of the Court of Judicial Review. Yun Zhiyi originally only wanted to keep her spice shop and make money to save her life, but discovers that her mother Qin Wannian did not die of illness five years ago, but was silenced for investigating the imperial palace's secret poison, "Snow Soul Powder". She opens the Zhiwei Pavilion, selling spices on the surface while secretly testing poisons and investigating cases, and pursues the poison chain behind the Marquis Manor, the Imperial Hospital, the Uncle of the State's Manor, and Noble Consort Rong alongside Pei Yanzhou. In the final showdown, Noble Consort Rong sets a trap for Yun Zhiyi to take the blame for poisoning the imperial heir.