The film begins with Flashman making a patriotic speech to the boys of Rugby School framed by a giant Union Flag, in a scene which appears to be a parody of the opening sequence in the 1970 film Patton. The film then follows the plot of the book, which itself largely derives from The Prisoner of Zenda. Flashman is forced to impersonate a Danish prince who is about to marry a German princess by Otto von Bismarck, partly in revenge for Bismarck's humiliation at the hands of Flashman in London; Flashman stole Bismarck's mistress Lola Montez, then manoeuvred him into boxing against a professional boxer, John Gully (played by Henry Cooper), at a house party. Bismarck does not wish the princess to marry a Dane, since this may tilt the balance on the Schleswig-Holstein Question and interfere with his plans for a united Germany.