A frail, asthmatic young Theodore Roosevelt transforms himself into a champion of the strenuous life, loses one great love and finds another, leads men into battle and then rises like a rocket to become the youngest president in American history at 42. Meanwhile, Franklin Delano Roosevelt, brought up as the pampered only child of adoring parents, follows his older cousin’s career with fascination.

Murder brings Theodore Roosevelt to the presidency, but in the seven years that follow, he transforms the office and makes himself perhaps the best-loved of all presidents, battling corporate greed, preserving American wilderness, carrying the message of American might around the world. FDR weds Eleanor Roosevelt, and jumps at the chance to run for the New York state senate.

Theodore Roosevelt leads a Progressive crusade that splits his own party, campaigns for American entry into World War I—and pays a terrible personal price. Franklin masters wartime Washington as Assistant Secretary of the Navy, while Eleanor finds personal salvation in war work. Her discovery of Franklin’s romance with another woman transforms their marriage into a largely political partnership.

Franklin Roosevelt runs for vice president in 1920 and seems assured of a still brighter future until polio devastates him. He spends seven years struggling without success to walk again, while Eleanor builds her own personal and political life of. FDR returns to politics in 1928 and acts with such vigor during the first years of the Great Depression that the Democrats nominate him for president.

FDR brings the same optimism and energy to the White House that his cousin Theodore displayed. Aimed at ending the Depression, his sweeping New Deal restores the people's self-confidence and transforms the relationship between them and their government. Eleanor rejects the traditional role of first lady, becomes her husband’s liberal conscience and a sometimes controversial political force.

FDR shatters the third-term tradition, struggles to prepare a reluctant country to enter World War II and, after the Japanese attack on Pearl Harbor, helps set the course toward Allied victory. Meanwhile, Eleanor struggles to keep New Deal reforms alive in wartime, and travels the Pacific to comfort wounded servicemen.

Frail and failing but determined to see the war through to victory, FDR wins re-election and begins planning for a peaceful postwar world, but a cerebral hemorrhage kills him at 63. After her husband's death, Eleanor Roosevelt proves herself a shrewd politician and a skilled negotiator in her own right, as well as a champion of civil rights, civil liberties and the United Nations.