1855. Edward Pierce (Sir Sean Connery), a member of London high society, is really a criminal mastermind. He is determined to steal the twenty-five thousand pounds sterling of gold shipped once a month via train by the handling bank, Huddleston and Bradford, from London to Folkestone on the coast, where it is shipped to Crimea as payment to the English troops, who, along with their French counterparts, are waging war there against Russia. There has never been a successful robbery on a moving train, which is considered folly by the authorities. Because of the nature of the safe in the luggage compartment of the train where the gold is kept, Pierce believes the easiest way into the safe is to obtain copies of the four keys required to open the safe, the four which are individually entrusted to three key people, who cannot know that copies have been made. Two are kept locked in the offices of the railway despatcher; one is kept in an unknown location by Huddleston and Bradford President, Edgar Trent (Alan Webb); and one is kept at all times around the neck of the bank branch Manager, Henry Fowler (Malcolm Terris), an acquaintance of Pierce's. Pierce needs the assistance of several people to pull off the heist, he enlisting: his beautiful mistress, Miriam (Lesley-Anne Down), who hopes the gold will mean a future for the two of them together; Robert Agar (Donald Sutherland), a screwsman; Barlow (George Downing), his chauffeur; "Clean Willy" (Wayne Sleep), a young cat burglar; and Burgess (Michael Elphick), the railway's security guard in the luggage compartment, who he will need to bribe to cooperate. Getting copies of the four keys is no easy task in and of itself, let alone getting the gold off the train undetected if they are able to get that far. They may have to turn to Plan Bs or Cs if they find the situation changes, and/or improvise on the spot if something doesn't work. But the large number of disparate individuals involved in the heist and the complexity of the plan may make the operation collapse under its own weight.