The tale unfolds with a quest: the young d'Artagnan sets out for Paris in pursuit of his fortune. Like many heroes of such journeys, he hails from noble ancestry but humble beginnings, relying on his wit and abilities to fulfill his destiny. Dreaming of joining the Musketeers, he must first prove he is worthy of the position. With the help of his father's friend, de Treville, he becomes a guard. His curiosity, initiative, and pride soon embroil him in a web of intrigue, ultimately allowing him to showcase his value and succeed as a Musketeer.

The book also presents another quest: the Musketeers band together to safeguard the Queen's honor, assisting her in concealing her affair with Buckingham and coordinating meetings with him. While this may seem trivial to contemporary readers when compared to the significant political issues of the era, the Musketeers' code of chivalry and honor dictates that nurturing true love is of utmost importance.

All the Musketeers view love as a noble condition, and they hold chivalry and honor in high regard. For example, their main task in the story is to help Queen Anne with her romance with the Duke of Buckingham, acknowledging their true affection. D'Artagnan develops feelings for Madame Bonacieux and encounters many risks while attempting to shield her from their mutual foes. Athos, who once cherished a woman, remains deeply wounded after discovering she was a treacherous thief who betrayed him.

Although the characters hold true love in high esteem, they display a notable lack of morality. A woman's marriage does not hinder their pursuit of true love; they are willing to engage in an affair if they find her sufficiently attractive. While they are fiercely loyal to each other, they have no qualms about killing their foes and show no remorse for the dead. Their principles of honor and integrity do not apply to their enemies. For instance, d'Artagnan would risk everything for Madame Bonacieux, yet he manipulates Milady into a romantic encounter for vengeance and deceives her maid, Kitty, by professing false love to extract information and assistance in his battle against Milady.