Historian David Reynolds examines Josef Stalin's handling of the conflict between the Soviet Union and Germany during the Second World War. First broadcast to mark the 70th anniversary of the Nazi invasion of the Soviet Union in 1941, Reynolds reassesses Stalin's role in the life-and-death struggle between the warring superpowers, which he argues was more critical for British survival than 'Our Finest Hour' in the Battle of Britain. He reveals how the dictator's mental frailties nearly caused his country to fall to the Nazis, and examines the compromises Stalin was forced to make to survive - dropping his Communist ideologies in favour of on appeal to the Russian people's nationalist fighting spirit. He also investigates the events that led to Stalin eventually siding with the Allies. The name Stalin means'man of steel' but Reynolds' penetrating account reveals that the man himself was anything but. Travelling to the sites of the main battles, he charts how Russia was almost annihilated within a few months as Stalin lurched from crisis to crisis, edging close to a nervous breakdown. Using original telegrams and official documents, he looks afresh at Winston Churchill's controversial visit to Moscow in 1942 and re-exomines how Britain and America were drawn into alliance with Stalin, a dictator almost as murderous as the Nazi enemy.