The film opens in a Battalion officers' mess#United Kingdom of an unnamed Highland Regiment in the early post-war era. Major (rank) Jock Sinclair (Alec Guinness) announces that this will be his last day as Commanding Officer#Army. Sinclair, who had been in command since the battalion's colonel was killed in action during the North African campaign during the Second World War, is to be replaced by Lieutenant Colonel Basil Barrow (John Mills). Although Major Sinclair led the battalion throughout the remainder of the war, Brigade HQ considered Barrow to be a more appropriate peacetime commanding officer.