In the year 1625, in Gascony, a province of France, a young man named d'Artagnan is taking leave of his father to journey to Paris, where he will seek out the prestigious Monsieur de Treville, captain of the King's Musketeers and a childhood friend of d'Artagnan's father.
D'Artagnan's father has only three gifts which he can give to his son: fifteen ecus in money, a ridiculous-looking horse about thirteen years old, and a letter of introduction to Monsieur de Treville. If d'Artagnan can convince Treville to allow him to become a musketeer, he believes that he will have his fortune made because the musketeers are a select group of swordsmen highly favored by the king.
After a sentimental leave-taking from his mother, d'Artagnan begins his journey to Paris. He arrives at the market town of Meung, where he sees an unknown nobleman who he believes is laughing at him, or at least at his horse. D'Artagnan's impetuous temper causes him to insult the nobleman and pick a quarrel with him. D'Artagnan is outnumbered, however, and before long he is carried unconscious into the inn. Learning from the innkeeper that d'Artagnan has a letter to the powerful Monsieur de Treville, the nobleman steals it from d'Artagnan's doublet.
When d'Artagnan recovers, he goes downstairs in time to see the nobleman talking with someone whom he addresses as "Milady." Later, d'Artagnan discovers that his letter of recommendation to Treville is missing, and after threatening the innkeeper and his servants, he learns that the mysterious nobleman ransacked his belongings and apparently stole the valuable letter of introduction. D'Artagnan departs, and when he arrives in Paris, he rents a room that he discovers is near the home of Monsieur de Treville.
This first chapter moves quickly. We see that our hero is a country boy, unaccustomed to the sophisticated ways outside of his little town; he is also from a section of France which is famous for its brave and daring young men. Throughout the novel, d'Artagnan's birthplace will be referred to as a place famous for producing men of exceptional courage, military valor, and quick tempers. D'Artagnan possesses all of these qualities — especially the latter. In fact, in the opening chapters of this novel, we see that d'Artagnan is so impetuous that he quickly embroils himself in a series of duels with three of the king's best swordsmen.
D'Artagnan's encounter with the as-yet-unnamed Count de Rochefort introduces us to the man who will become d'Artagnan's mysterious nemesis (enemy). However, until the end of the novel, Rochefort will be referred to only as "the man from Meung." At the end of the novel, when ordered to do so by Cardinal Richelieu, Rochefort and d'Artagnan will put aside their differences and become allies and friends.
The puzzling appearance here of "Milady" will become even more important to the plot than d'Artagnan's chance encounter with Rochefort; Milady will play a major, pivotal role later in the novel. The ultimate importance of both of these mysterious characters suggests that Dumas had the plot of his novel well outlined before he began writing it.