Nan Yan is a disciple of the Yangyue Sect, a righteous sect. She is known as the Deadly Poison Master because she is good at using poison to treat diseases. One day, she unknowingly absorbs the Seven Sins Manual, a magic-killing technique, into her body. Shao Cang is the former emperor of the Great Path Sect, the world's number one sect. He was convicted and expelled from the sect for killing fellow disciples and adopting the devil's way. After escaping from the Soul River's underwater prison, he goes to the North to find the long-lost Seven Sins Manual, which is believed to punish evil and uphold the Path. Outside the Filth Valley, Shao Cang comes across Nan Yan trying to flee from Yu Yong of the Evil Path Sect. Shao Cang secretly saves Nan Yan but overexerts his inner strength during his fight against the evil sect. Nan Yan finds the unconscious Shao Cang and discovers he has the same heart disease as her mom. She secretly brings Shao Cang back to her home in Mount Yangyue to use him as a medicine tester. (Source: Chinese = Baidu || Translation = AnastasiaWun at MyDramaList)