Sir Sidney Ruff-Diamond looks after the British outpost near the Khybar pass. Protected by the kilted Third Foot and Mouth regiment, you would think they were safe, but the Khazi of Kalabar has other ideas—he wants all the British dead. But his troops fear the 'skirted-devils, who are rumoured not to wear any underwear.

Although loudmouthed braggart Jerry Plunkett alienates his comrades and officers, Father Duffy, the regimental chaplain, has faith that he'll prove himself in the end.

As soon as they arrive at the barracks, the new contingent reveals some characters who will give their officers a hard time. There is the handsome, resourceful man, the technocrat in love, the bootlicker, the "Jamaican" who only moves to music, the shortsighted man... and all the others. Sometimes to see the nurse undress, sometimes to arrange an appointment with a fiancée, sometimes to cuckold the obtuse non-commissioned officer whose wife is volcanic, sometimes to have a free lunch in a great restaurant, the handsome man invariably deploys a wealth of cunning. And each time it is the colonel's servile driver who gets caught instead of him.