A secret World War II document opens Elizabeth’s eyes to grim realities about a family member. The Duke of Windsor campaigns to re-enter public life.

When Elizabeth and Philip throw a grand party for their 10th anniversary, both Margaret and the new Prime Minister experience romantic tribulations.

Margaret and Peter are reunited, but another obstacle stands in their way. Elizabeth is torn between her duty as Queen and her love for her sister.

Margaret and Peter come to Elizabeth with a request. With a royal scandal about to break in the newspapers, the Queen Mother intervenes.