It's war time London and the Crazy Gang (Flanagan & Allen, Nervo & Knox, Naughton & Gold) are doing their bit for the war effort by running a fish and chip stall using their platoon's barrage balloon for advertising. Their Sgt Major is not happy about this and orders them to take the balloon down, but a freak heavy wind accidentally carries the gang away to Nazi Germany. They are captured and placed in a detention camp where they meet an elderly prisoner named Jerry, who possess a map for the location of a secret weapon which will win the war! Fortunately Teddy Knox's impersonation of Hitler lands him the spot of pretending to be the Fuhrer at a gala dinner and the gang are allowed out of the camp. However the Nazis have other ideas for their substitute leader.