Belonging to the reigning house of the Manchu emperors, Orchid, whose real name is Du Wang, on the instructions of Empress Ci Xi, enters the Embassy Quarter of Beijing at the time of its siege and falls in love there with the French diplomat Edward Blanchard. Having betrayed the empress, she and her lover go to Paris. The couple lives happily on Velazquez Avenue, until one day Orchid receives a letter in which she is ordered to return to Beijing, having previously stolen a precious relic of the Manchu dynasty, stolen by Europeans, from the Cernucci Museum. Overcoming fear, she copes with the task alone, but upon returning home she finds the corpse of her husband... Orchid is accused of murder. But the heroes of the 2 previous novels of the trilogy intervene in the matter - the artist-spy Antoine Laurent, the journalist Lartigue and the conductor of the Mediterranean Express Pierre Beau. Friends are doing everything to uncover the mystery of the death of Orchid's husband and save the heroine herself.