Charles and his family gather following the funeral of Queen Elizabeth II. Charles, as the new king, then holds his first weekly audience with Prime Minister Tristan Evans. They discuss a new Bill for statutory regulation of the press, which has passed the House of Commons and the House of Lords and awaits only Charles' royal assent to become law. Charles is concerned that the law restricts freedom of the press too much, and would allow the government to censor the news and prevent legitimate uncovering of abuse of power. He asks the PM for alterations to the bill, but the PM refuses. As the two men spar, Mrs Stevens, the Leader of the Opposition, arrives for a weekly meeting with Charles, an innovation the new king has introduced. Stevens expresses her own doubts on the bill, and despite reminding the king of his level of power, she sees little alternative but for Charles to sign.
In parallel, Prince Harry has begun a relationship with Jessica Edwards, a working class republican who has made him reconsider his desire to remain a member of the royal family. Jess later approaches royal press adviser James Reiss about an ex-boyfriend of hers, who is threatening to leak compromising photographs of her which she fears could damage both her and the prince's reputation. Both Charles and Prince William have seen the ghost of Princess Diana, promising each man that he will become "the greatest king of all". One of Charles' first actions is to refuse to give royal assent to the press regulation bill. The Prime Minister holds a crisis meeting with the Leader of the Opposition and then goes alone to try to convince Charles to sign, but Charles continues to refuse. Evans then threatens to pass a new law bypassing the royal assent and then pass the press law. However, just prior to the vote, Charles enters the chamber and uses his power of the royal prerogative to dissolve Parliament, preventing the PM from bringing either plan into effect. Charles' actions are reluctantly supported by Douglas Rowe, the Speaker of the House of Commons, who subsequently refuses to allow the parliament to re-assemble.
Protests begin across the country, with the most violent taking place in London. In response, Charles increases the army guard at Buckingham Palace, a move which only further increases the tension between him and the British government. He then offers royal protection to Jess, whom the media have made the centre of a sex scandal after her ex-boyfriend leaked the photos to The Sun. He also agrees to Harry's wish to become a commoner, so he can live a more fulfilling life with Jess. The PM, increasingly concerned with the backlash as a result of the king's actions, meets with William, Prince of Wales and Catherine, Princess of Wales to discuss the matter. Catherine, not wanting to lose the opportunity to rule alongside William in the future, proposes a solution: William will serve as a mediator between Parliament and his father. William joins his father in a press conference, where he announces the plan without the king's knowledge or consent. Seeing this as a betrayal, Charles reacts angrily to both his son and press adviser James Reiss. During a tense meeting with William, William angrily rebukes his father for creating disorder, as well as chastising him for his mistreatment of Diana during her lifetime and asks him to abdicate to help restore order. As Catherine and Harry await in another room in Buckingham Palace, the three deliver an ultimatum to the king, threatening to remove themselves (and their children) from his life unless he steps down. Unwilling to face the rest of his life alone, Charles reluctantly abdicates in favour of William, who plans to sign the press bill and restore the status quo between the monarchy and Parliament, in addition to quelling the public unrest. Prior to the joint coronation at Westminster Abbey, Harry meets with Jess and reluctantly informs her they can no longer be together, as their former plans would upset the status quo with the new king and his position in the public sphere. The film ends with William and Kate's coronation as king and queen consort, with Charles angrily placing the crown on his son's head in lieu of the Archbishop of Canterbury before exiting as the crowd proclaims "God Save the King".
Royal Family
Tim Pigott-Smith as King Charles III
Oliver Chris as William, Prince of Wales
Richard Goulding as Prince Harry
Charlotte Riley as Catherine, Princess of Wales
Margot Leicester as Queen Camilla
Katie Brayben as the ghost of Diana, Princess of Wales
Politicians and public figures
Adam James as Prime Minister Tristan Evans
Priyanga Burford as Mrs Stevens, the Leader of the Opposition
Ian Redford as Douglas Rowe, the Speaker of the House of Commons
John Shrapnel as the Archbishop of Canterbury
Rupert Vansittart as Sir Matthew, a British Army General
Others
Tim McMullan as James Reiss, the Press Adviser to Buckingham Palace
Tamara Lawrance as Jessica Edwards, Prince Harry's republican girlfriend
Max Bennett as Coottsey, a friend of Harry
Parth Thakerar as Spencer, a friend of Harry
Tom Mothersdale as Bob, Jess's equally republican flatmate
Nyasha Hatendi as Paul, the owner of a takeaway restaurant
adapted by Mike Bartlett from his play of the same title