 One flashback scene of the film, set in 1936, sees Rina and Michaili, in what appears to be an alpine setting in Europe, escaping being bombed by Nazi planes, despite the date preceding the aerial warfare of the Second World War.Wu himself has said that the film is "both true and untrue" in that it is a composition of fiction and history; "the main characters were all based on real prototypes…I can’t promise it's 100% accurate, but I think it fits the background of the time.