Following World War II in peacetime Scotland, brigade headquarters replaces commanding officer Major Jock Sinclair, a boisterous battalion leader, with the strict, temperamental Lieutenant Colonel Basil Barrow. Resentful toward his replacement, Sinclair undermines Barrow's authority and damages his successor's reputation among the soldiers. Barrow faces an uphill battle in regaining the discipline and respect of his battalion.

In 1940, the Royal Air Force fights a desperate battle against the might of the Luftwaffe for control of the skies over Britain, thus preventing an attempted Nazi invasion.