Summer 1939. Translator Harry (Jonah Hauer-King) is working at the British Embassy in Warsaw, falling in love with Polish waitress Kasia (Zofia Wich?acz). When German tanks roll into Poland and Britain declares war on Germany, Harry and Kasia are faced with terrible choices.

Paris, France, 1899. The corpse of an unknown woman is found in the river Seine. The investigation will push a young ambitious inspector to discover a heavy state secret.