In 1702 London, a gentleman's club puts on a raucous satire mocking Princess Anne and her recent phantom pregnancy. Afterwards, Abigail Hill meets Jonathan Swift and her cousin Robert Harley, a Tory and the Leader of the House of Commons. Harley agrees to win her a position in Anne's household by introducing her to Anne's confidant Sarah Churchill, in return for her supplying him with information. Meanwhile, Sarah describes to her husband John Churchill, (Duke of Marlborough) her visit to Sophia of Hanover, presumed to be second in line to the throne due to Anne's continued childlessness. William III tries to force his sister-in-law Anne into accepting a visit to London by Sophia, despite Anne's misgivings about what message this will send out regarding her own position in the succession, but it takes Sarah to win Anne round to the idea.
Soon afterwards William dies in a riding accident and Anne comes to the throne. Initially advised by Sidney Godolphin, Sarah and the Whigs, she is later won round to replacing him with Harley and following a more Tory line, such as supporting the anti-Whig Occasional Conformity Act 1711 and the Act of Union of 1707. In revenge for Godolphin's dismissal and Anne's perceived lack of sympathy for Sarah's son's death, Sarah has Arthur Maynwaring write a damning and sexually explicit satire of Abigail's influence over Anne alleging that they have a lesbian relationship - Abigail has in fact gained and kept Anne's trust by never talking politics. Sarah shows this to Anne but later Abigail privately reveals that she knows Maynwaring and Sarah are behind it. Harley arranges for Swift to produce a satire aimed against Sarah and her husband, alleging their embezzlement of army funds to build Blenheim Palace.
Sarah is then forced to resign her position of Keeper of the Privy Purse but relations sour between her and her husband when he does not resign in support of her. Sarah plans to publish her correspondence with Anne to avenge her dismissal, but this is thwarted and John decides to flee England rather than stay and face a trial. Sarah attempts one final meeting with Anne, but their relationship remains broken as Sarah makes one final defiant monologue to the audience.