Set in the decadent 1920s, Temptress Moon tells the very complicated story of a wealthy family living on the outskirts of Shanghai. Their youngest daughter, Ruyi, is brought up as a servant to her opium-addicted father and brother. Meanwhile, her brother-in-law Zhongliang has a successful, if illegal, career seducing and blackmailing married women in the city. When he comes to Ruyi's home the two fall in love, and trouble ensues.

The story of the Opium War between China, in the waning days of the Qing Dynasty, and the British Empire, in the 1830s, and the subsequent takeover of Hong Kong by Britain; through the eyes of the key figures, fiercely nationalistic Lin Zexu, and opportunistic British naval diplomat Charles Elliot.