On the Double is an adventure war movie with a comedy twist. It is about the adventures of an American soldier. An American soldier has a reputation for imitation and disguise. He looks almost exactly like a British Colonel. He is requested by his superiors to take the place of the Colonel. The explanation is that the Colonel must travel to the East as part of his duties but does not want it known. The recent attempted assassination is not in the briefing.
The focus of this movie is on the abilities of an American to be a British Colonel. This soldier must fool the enemy just long enough for the ploy to work.