In January 1942, the historic Achnacarry Estate was transformed into a wartime paramilitary academy. In four years of operation, 25,000 men came to the Scottish Highlands to endure the world's toughest infantry training course. Narrated by Rory Bremner, Castle Commando looks back on the larger-than-life characters that helped shape Winston Churchill's legendary raiding troops. Veterans remember how the ferocious Highland landscape was the perfect environment for the most exacting, most gruelling military training of World War II.