Philandering British Intelligence officer Commander Max “Rammer” Easton (James Mason) – now desk-bound and under-worked in the Admiralty – finds he suddenly needs to make some money to woo fancy American woman Virginia Killain (Vera Miles).
He hatches a plot to disappear in circumstances that suggest he has defected to the Soviets with top-secret information and then return to sue the newspapers for libel.
Easton takes his small sailing boat, the Shelduck, to a remote Scottish island and sinks it after setting up a comfortable temporary home on the rocks, complete with tent, stove and radio (and champagne) and settles down in relative grandeur lunching on lobster and wine while Whitehall becomes increasingly nervous and the media take the bait.
Once they publicly call him a traitor, Easton throws his stockpile of luxury goods into the sea and prepares to light a bonfire that will summon rescuers – but accidentally loses his accelerant and is forced to try lighting a pile of soggy seaweed – eventually running out of matches.
He must now sit and endure the harsh Scottish weather with no shelter or food while the scandal of his treachery fills the newspapers.
He is eventually rescued and his reputation redeemed, but the police suspect him of doing exactly what he did. There are some narrow escapes but he suavely bluffs his way through and everything works out satisfactorily.
Easton gets the girl and instead of suing the media, he sets about making his fortune by writing the “true story” of his adventure.
Cmdr. Max Easton
Sir Charles Holland
Cmdr. John Larkin
Gregson (Special Branch)
Sub Lt. Brown