It recounts the adventures of a young man named d’Artagnan, after he leaves home to become a musketeer. D’Artagnan is not one of the musketeers of the title; those are his friends Athos, Porthos, and Aramis – inseparable friends who live by the motto, “One for all, and all for one”.
A young man from Gascony named D’Artagnan sets out for Paris with three gifts from his father: fifteen crowns, a horse, and a letter of introduction to M. de Tréville, who is a Very Important Person since he commands the King’s Musketeers. D’Artagnan hopes to become a Musketeer one day, but he doesn’t have much going for him except for his training as a gentleman, which means, effectively, that he can handle a sword and be polite about it. His pluck, determination, and good manners lead him to become BFF with three Musketeers named Porthos, Athos, and Aramis, and also lead him to fall in love with the beautiful Constance Bonacieux.
Meanwhile, the Duke of Buckingham is wooing Queen Anne of France. Since they can’t exactly be public about their feelings for each other – because she’s married to the King of France -, Anne gives him some diamond studs as a consolation prize during his trip back to England.
The nefarious Cardinal, who’s still angry that Anne burned his declarations of love some time back, wants her to get in trouble with her husband. He knows, through his spies that Anne gave the diamonds to Buckingham. He suggests that the King throw a fête – party – and require Anne to wear the diamonds. As soon as Anne finds out about this fête and this requirement, she bursts into tears…