At the court of Charles II, young John Churchill advances his career by serving the king’s bastard son, Monmouth, in the field of battle, and by bedding the king’s mistress, the Duchess of Cleveland. Young Sarah Jennings is also advancing at court, by befriending the king’s sister-in-law, the Duchess of York, and teaching the York princesses, Mary and Anne, the art of gambling. At a court masque, the two meet, and sparks fly.

In 1675 a masque was performed at the Court of Charles II at Whitehall. There the young soldier John Churchill, Groom of the Bedchamber to the King's brother, fell in love with a pretty lady-in-waiting, Sarah Jennings.

John and Sarah have married. Lord Shaftesbury has threatened Charles with rebellion. To appease his Protestant Parliament, Charles has arranged a marriage between Mary and the Prince of Orange.

The rage against Popery in England continues. James, Duke of Monmouth, has become the protégé of Shaftesbury who plans to make him King. But Churchill has refused to support Monmouth. Charles has resisted all pressure to disinherit his brother James.

Charles has been forced to send James into exile and to dissolve his factious parliament at Oxford. The Princess Anne has married George, Prince of Denmark, and has chosen Sarah to be one of her Ladies of the Bedchamber.