Hapless new army recruits Jimmy Jervis and Ben Watts happily find themselves stationed at the same base as Ben's sister, Joan.

The clueless pair are a constant thorn of irritation in the side of Sergeant Locke, but unknown to all much more nefarious goings-on are afoot on the camp.

Sergeant Kirk is an habitual gambler and has been on a particular string of bad luck recently. He's just about keeping his bookies happy, debts in other areas of his life are beginning to mount and the owner of the local general store is insistent he pay off some of his account before any more goods are sold to him.

Stuck, he finds himself tempted by a large sum of money left in an adjoining office safe by Captain Whitfield, and concocts a plan to pinch it and set up someone else on the base to take the fall.

Joan ends up the unlucky recipient of a duplicate key for the safe, and after the money is found missing and a kit inspection ordered, she sure enough is put on trial - but Kirk has not reckoned on upset of a woman scorned, the hapless antics of Privates Jervis and Watts, or his own mysterious past!