Based on Geoffrey Household's rather far-fetched book, Peter O'Toole is British aristocrat "Sir Robert" who lays plan to assassinate Adolf Hitler before the start of WWII. After missing an open goal his plan goes awry, and after some fairly brutal torture at the hands of his captor Michael Byrne, he manages to flee the scene of his own proposed demise and to make it back to Blighty where his solicitor and kindly uncle (Alastair Sim) recommends he keep his head down for fear his plot be publicised, and the country be dragged into war...! The Nazis have not, however, given up on their chase…