The Duke pieces together the full story of the situation, and expresses his astonishment that the Cardinal’s agents didn’t stop D’Artagnan. D’Artagnan points out that he had three brave friends with him. Still, the Duke is impressed.
The two of them reach London and head for the Duke’s house.
The Duke takes D’Artagnan to the shrine he has dedicated to Queen Anne. This shrine contains a life-size portrait, an altar, and the casket with the diamond studs.
The Duke kneels in front of the portrait and retrieves the studs. He begins kissing each of them when he notices that two are missing.
The Duke is convinced that the Cardinal had them stolen. He remembers that he wore the studs recently to a ball where he spoke with the Comtess de Winter (otherwise known as Milady), an agent of the Cardinal.
But there are still five days before Queen Anne has to wear the diamonds. The Duke calls for his servant, Patrick, and asks for his jeweler and secretary.
He orders his secretary to put through a law that no ships are to leave the port. This amounts to a declaration of war against France, but hey: a woman’s honor is at stake. If the two missing diamonds are still in the country, they will arrive in Paris only after D’Artagnan does.
D’Artagnan pauses for a moment to mention the fact that the Duke is abusing power in order to pursue the Queen. The Duke says, yes, that’s right, I would do anything for her. Then he lists all the things he would do.
The jeweler shows up and the Duke asks him to create two diamond studs identical to those missing. He give the jeweler two days and double the usual price.
And then the Duke "asks" the jeweler to stay in the castle while he works, (which means that the jeweler is effectively a prisoner until the diamond studs are finished). The Duke throws in some more money for good measure.
The two men then go to bed—D’Artagnan sleeps in an adjoining room so that the Duke can rave to him about the Queen.
Soon the two diamond studs are finished, and D’Artagnan is ready to go back to Paris. The Duke then asks what he can do for D’Artagnan.
D’Artagnan is very uncomfortable with the idea of being paid with English money. He tells the Duke, a) that he serves in a military company loyal to the King and Queen of France, b) that the only reason he agreed to this mission was to serve the Queen, and c) that his (D’Artagnan’s) actions help him woo a very nice young lady.
D’Artagnan also points out England and France are now at war, and that the two of them are enemies.
The Duke responds by saying that D’Artagnan is very proud. He then gives D’Artagnan detailed instructions for getting back to Paris that involve lots of passwords.
D’Artagnan gets back in no time, and checks in with Tréville, who tells him that he should join Dessessart’s company on duty at the Louvre.