The King is outraged when he hears about Buckingham’s visit. The Cardinal pretends to think the Queen did not see Buckingham, but he also mentions that the Queen spent the morning writing a personal letter. When the Cardinal suggests having the Queen's room searched for this letter, the King agrees, thinking that this is a good way to catch his wife in the act of communicating with her lover.

Meanwhile, the Queen sits in her room thinking about how awful her life is. The Cardinal has tormented her for years, ever since she refused to have an affair with him. Part of her wishes she had simply given in and done what he wanted, but she knows that he would have tormented her anyway as soon as their romance ended. The Cardinal always uses the King, who is not too smart, to drive away her loyal friends and servants. Because of this, she is always alone.

As the Queen is thinking this, the King bursts in and announces that he is having the Queen’s rooms searched. Then the King’s chancellor, Séguier, enters and searches the Queen’s desk. This is a mere formality because he knows that the Queen would never leave a secret document lying around in a drawer. She admits that she is carrying a letter in her clothing, but she refuses to hand it over. She does not think that he would dare to conduct a physical search on a woman of her royal position, but he says that he has been authorized to do exactly that. This horrifies her, but she hands over the letter.

Séguier takes the letter to the King, who reads it eagerly. It turns out that Queen Anne has been writing to her father about a plot to bring down the Cardinal. She asks her father to pressure Spain and Austria to threaten war on France unless the Cardinal is immediately fired. This letter proves that the King’s wife has been plotting treason, but he does not care. In his mind, it would be far worse for her to have an affair.

The King shares the letter with the Cardinal, who does not seem terribly concerned by the threat it implies to him personally. He suggests that the King apologize for having the Queen searched and offer to throw a ball to make it up to her. The King follows this advice but leaves it to the Cardinal to set a date.

The Cardinal, meanwhile, waits for a letter from Milady. When he hears that she has the diamond studs and is heading for Paris, he tells the King to hold the ball a day or two after Milady will arrive. The Cardinal then casually suggests that the King ask the Queen to attend the ball wearing the diamonds he gave her for her birthday. Clearly the Cardinal wants the King and his ball guests to find out that the Queen gave her diamonds to the Duke of Buckingham. If his plan succeeds, it will shame the Queen forever and weaken the people’s respect for their King.