The first episode in the series tells the story of how Winston Churchill came to write Marlborough, his million-word biography of his ancestor John Churchill. The first volume describes how John rose from obscurity to be the right-hand man of King James II. But in the crisis of 1688 John chose political principles over personal loyalty and betrayed James in the so-called Glorious Revolution that set Britain on the course to democracy, and committed her to war with the rising hegemonic power of Louis XIV's France. Dr David Starkey argues that it was Winston's absorption in the 17th century that helped him to be the first to recognise the menace of a new European hegemony, warning Parliament about the Nazis before Hitler had even come to power.

Dr David Starkey shows how Winston Churchill's biography of his ancestor John Churchill - which was also serialised in the Sunday Times - changed the way Winston was seen by the public and politicians, and so prepared the way for his return to power. The first volume reinforced the perception of him as a man past his time, a warmonger. But the second volume, with its brilliant depiction of John Churchill's march to the Danube and stunning victory at Blenheim, began to mark out Winston as the only leading politician who truly knew war. As further volumes appeared, and the threat from Hitler became obvious, people increasingly began to see Winston as the man of the hour.

The final episode in the series shows how Winston Churchill drew on the lessons of John Churchill to fight World War II. At two key moments in particular, Winston's strategic sense averted disaster, and in both decisions, the influence of the Duke of Marlborough is apparent. Dr David Starkey argues that it was Winston the historian's ability to control events by naming them and giving them a narrative meaning than enabled him to shape world history long after his own fall from power, right up to the present day.