The three musketeers have little to do because they are not yet involved in the siege, so they ride out to a neighboring inn. On the way back, they challenge an approaching rider who, in turn, challenges them with a voice of absolute authority. It is the cardinal. Surprisingly, he knows the names of each of the three musketeers; because his mission is secret, he asks them to accompany him in order that his safety be guaranteed. He knows their reputations for bravery, loyalty, and trustworthiness.
They learn that he is going to the inn which they just left, and they tell him about some rogues who tried to break into a lady's room. The musketeers were obliged to disperse these unsavory characters. The cardinal is pleased; the lady is the very person whom he is to meet. He asks the musketeers to wait for him in a room below while he goes up to talk to the lady.
In the musketeers' room, there is a broken stovepipe and, by accident, Athos discovers that he can hear the conversation between the cardinal and Milady. Porthos and Aramis also draw up their chairs and listen. They hear the cardinal tell Milady that she is to go to London to contact Buckingham and let him know that as soon as he attacks France, the cardinal will bring about the queen's ruin. Milady is also to tell Buckingham that the cardinal knows about his activities with the queen, and he describes each meeting which the duke has had with the queen, including a description of the clothes that the duke wore on each occasion. The cardinal also knows the truth about the diamond tags.
