Sergeant Grimshaw (William Hartnell) is about to retire. He's never succeeded in having a squad under his command pass out top of the training course. He accepts a bet from another sergeant that this time, his last chance, he will succeed. He's dismayed when his squad arrives: Horace Strong (Kenneth Connor) is a hypochondriac; Charlie Sage (Bob Monkhouse) is an extremely reluctant recruit, having received his call-up papers during his wedding reception; Miles Heywood (Terrence Longden) thinks only about women; Andy Galloway (Gerald Campion) is a pop singer; Peter Golightly (Charles Hawtree) is incredibly clumsy and James Baily (Kenneth Williams) thinks the army is an anachronism, and sets out to prove it. After a great many mishaps the sergeant gradually knocks his unpromising material into shape. When they realise what's at sake for the old soldier, they try to do their very best at the passing out parade.