As World War II settles over England, university student Stanley Windrush (Ian Carmichael) receives his call-up. During training, Windrush is plunged into a thoroughly unfamiliar world, with his leading officer, Maj. Hitchcock, more apt to be found in a pub than on the base. There's also Pvt. Percy Fox (Richard Attenborough), a cunning working-class type always on the make, and the cold and crafty Bertram Tracepurcel (Dennis Price). All are being trained for an unusual mission inside Germany.