The plot is based on Cao Yu's 1934 play Thunderstorm (pinyin: Lei Yu), but is set in the imperial court of the Later Shu, which was during the turbulent Five Dynasties and Ten Kingdoms Period. Emperor Ping is a man of humble origins and strong ambition, having risen to the throne from the lowly rank of captain. He abandoned his first wife to marry the Princess of Liang, who is now his Empress Phoenix. The Emperor does not love his second wife or her often sour mood; he blames the latter on an illness, for which he has forced her to take medicine of his own concoction every two hours for the past ten years. Empress Phoenix has been outwardly obedient throughout the marriage and her husband's treatment, but has grown suspicious of the medicine in the recent span of ten days. Her submissiveness also conceals the fact that she and Crown Prince Wan, the Emperor's son from his previous wife, have engaged in an illicit affair for three years. The status quo is broken, however, when Wan reveals to the Empress his guilt about the affair and then ends it against her wishes. Part of his motivation is a second secret relationship, held with Jiang Chan the daughter of the Imperial Doctor. Wan's overriding desire is to escape the palace, which he has never left, and thereby see the outside world with Chan.