Su Yishui, a talented young cultivator, had his destiny changed by his master Mu Qingge eighteen years ago. Mu Qingge, known as the "female demon," was also branded with a bad reputation and presumed dead. Eighteen years later, Mu Qingge transforms into Xue Ranran, and Su Yishui, now the head of the West Mountain Sect, takes the critically ill Ranran as his disciple, vowing to protect her for life. Thus, the roles of master and disciple are swapped, and various amusing and unusual stories unfold between them.

During wartime in Republican-era China, a young Communist spy and a clever pharmacy worker join forces to uncover enemy secrets. Using art forgery and sharp instincts, they risk everything to sabotage a Japanese military plan and protect their homeland.