In early 1939, before the start of the Second World War, Sir Robert Hunter (O'Toole) takes aim at Adolf Hitler with a hunting rifle but misses when he is spotted and tackled by a ''Schutzstaffel'' (SS) guard. Captured and tortured by the Gestapo, he is left for dead but manages, with the aid of a friendly German people sportsman, to make his way back to England. To his surprise, he discovers the Gestapo has followed him. Believing that the government would turn him over to German authorities, Sir Robert goes underground (literally) to escape his pursuers.