
American GI Ernie Williams, admittedly weak-kneed, has an uncanny resemblance to British Colonel MacKenzie. Williams, also a master of imitation and disguise, is asked to impersonate the Colonel, ostensibly to allow the Colonel to make a secret trip East. What Williams is not told is that the Colonel has recently been a target of assassins. After the Colonel's plane goes down, the plan changes and Williams maintains the disguise to confuse the Nazis about D-Day.

as Pfc. Ernie Williams

as Lady Margaret MacKenzie-Smith

as Colonel Somerset

as Lady Vivian

as Sergeant Bridget Stanhope

as Captain Patterson

as Corporal Joseph Praeger

as Colonel Rock Houston

as Sergeant Colin Twickenham

as General Carleton Brown Wiffingham

as Oberkommandant

as Blankmeister

as Mrs. Somerset

as General Zlinkov