In the aftermath of the Slapton Sands disaster, Hugh Kelso, a US Army colonel, is washed ashore on Jersey, He is rescued by Hélène de Ville, who contacts London. Brigadier Dougal Munro of SOE is aware that Kelso is one of the few officers who know the details of the planned D-Day landings. He decides that Kelso must either be rescued or eliminated.