The story follows Elizabeth Windsor as she unexpectedly becomes the Queen of the United Kingdom following the death of her father, King George VI. Set against the backdrop of post-war British society and a waning empire, the series begins with her early reign and marriage to Prince Philip, Duke of Edinburgh. As Elizabeth grapples with assuming her responsibilities as the nation's leader, she confronts a myriad of challenges. Not only must she navigate political landscapes and constitutional dilemmas but also manage tensions within her own family. Her marriage and personal relationships undergo significant stress due to her newfound responsibilities and the scrutiny they bring. The series delves into Elizabeth's dynamic with Prime Ministers Winston Churchill and Anthony Eden, highlighting the balance she must strike between tradition and modernity.

As the narrative progresses through the decades, it examines historical milestones and their impact on both the monarchy and British society. From the Suez Crisis to internal palace intrigues, each episode dissects the challenges Elizabeth encounters, including dealing with her growing family and evolving societal norms. Amid a rapidly changing world, Elizabeth must maintain the crown's relevance while addressing scandal, political tension, and public opinion. Her relationship with other key figures in the royal family, such as her sister Princess Margaret, is portrayed with complexity, adding layers to their bond shaped by duty and personal desires. Through these dramatic retellings of real events, the series paints an intimate portrait of endurance and adaptation, revealing how a singular monarch balances her personal identity with the immutable weight of monarchy's traditions.