A young Princess Elizabeth marries Prince Philip. As King George VI’s health worsens, Winston Churchill is elected prime minister for the second time.

With King George too ill to travel, Elizabeth and Philip embark on a four-continent Commonwealth tour. Party leaders attempt to undermine Churchill.

When dense smog cripples London for days and creates a serious health hazard, Churchill’s inaction leaves him vulnerable to his political enemies.

Elizabeth rejects protocol by appointing Philip to coordinate her coronation, but his ideas create conflict. The Duke of Windsor returns to London.

As tensions with Philip increase, Elizabeth spends time with her old friend Porchey. Churchill’s portrait is painted for his 80th birthday.