In the England of James I, it is better to keep one's own counsel, especially when the Gunpowder Plot is afoot. Lady Elizabeth Cary has been invited for a stay at Baynards Castle by her friend and mentor Countess Mary Herbert. The two are attending a play at the Globe when Countess Mary's son Philip appears and tells his mother of the plot against the king. When the play ends, Countess Mary's party returns to Baynard's, where all await news of the night's events.
The residents of Baynards Castle have their secrets, and when she visits her friends, Lady Elizabeth has secrets too. There is a well-known late-night visitor in the castle whose presence might bring scandal. Lady Elizabeth is keeping money that belongs to her father's servingman, Toby Jones, in an arrangement that could anger her husband's family. Sir Henry Cary is being held for ransom by the Spanish, and it has been over two years since Elizabeth has seen him.
The one secret Elizabeth is considering confiding to Countess Mary has to do with her growing desire to write her own play. When she attends the theater with her friend, she sometimes imagines that they are watching a play written by herself rather than Master Will Shakespeare.