Having learned swordsmanship from his father, the young country bumpkin d'Artagnan arrives in Paris with dreams of becoming a king's musketeer. Unaccustomed to the city life, he makes a number of clumsy faux pas. First he finds himself insulted, knocked out and robbed by the Comte de Rochefort, an agent of Cardinal Richelieu, and once in Paris comes into conflict with three musketeers, Athos, Porthos, and Aramis, each of whom challenges him to a duel for some accidental insult or embarrassment. As the first of these duels is about to begin, Jussac arrives with five additional swordsmen of Cardinal Richelieu's guards. D'Artagnan sides with the musketeers in the ensuing street fight and becomes their ally in opposition to the Cardinal, who wishes to increase his already considerable power over the king, Louis XIII. D'Artagnan also begins an affair with his landlord's wife, Constance Bonacieux, who is dressmaker to the Queen, Anne of Austria.
Meanwhile, the Duke of Buckingham, former lover of the Queen, turns up and asks for something in remembrance of her; she gives him a necklace with twelve settings of diamonds, a gift from her husband. From the Queen's treacherous lady in waiting, the Cardinal learns of the rendezvous and suggests to the none-too-bright King to throw a ball in his wife's honor, and request she wear the diamonds he gave her. The Cardinal also sends his agent Milady de Winter to England, who seduces the Duke and steals two of the necklace's diamonds.
Meanwhile, the Queen has confided her troubles in Constance, who asks d'Artagnan to ride to England and get back the diamonds. D'Artagnan and the three musketeers set out, but on the way the Cardinal's men attack them. Only d'Artagnan and his servant make it through to Buckingham, where they discover the loss of two of the diamond settings. The Duke replaces the two settings, and d'Artagnan races back to Paris. Porthos, Athos, and Aramis, wounded but not dead as d'Artagnan had feared, aid the delivery of the complete necklace to the Queen, saving the royal couple from the embarrassment which the Cardinal had plotted.
Captain TrÃ©ville eventually inducts d'Artagnan into the Musketeers of the King's Guard.
who has confided her troubles in Constance, who asks d'Artagnan to ride to England and get back the diamonds?
the queen