After searching for the man from Meung for a half hour, d’Artagnan returns to his apartment where his friends are waiting, including Aramis, who made his way to the apartment while d’Artagnan was out searching. Upon returning, d’Artagnan sends Planchet downstairs to get some wine from Monsieur Bonacieux and then starts to tell his friends about his new mission. Together, they discuss the queen’s affair with the Duke of Buckingham, who has apparently arrived in Paris recently. The musketeers believe that the cardinal is attempting to trap the duke and that the stranger from Meung is somehow involved. Aramis relates an incident that occurred the day before where he escorted a woman to her carriage and was approached by a group of men who thought he was the duke. The group was led by the stranger from Meung.
D'Artagnan immediately takes advantage of his new acquaintance by getting Planchet to fetch him some wine. Upon talking to the musketeers, d’Artagnan quickly realizes that Monsieur Bonacieux’s version of events has merit. Indeed, the cardinal and the man from Meung are involved in some type of scheme against the queen and the Duke of Buckingham. Although the cardinal is the king’s rival, the two of them still share political goals and generally act in unison. However, here, the cardinal is taking serious steps to undermine the queen. At this point, his motivation is unclear, although it is revealed later in the novel.
As d’Artagnan and his friends attempt to figure out what happened to Madame Bonacieux, they are interrupted by Monsieur Bonacieux, who yells for help. Several of the cardinal’s men have arrived to arrest him. D’Artagnan runs to Monsieur Bonacieux and tells him to be quiet and go willingly. D’Artagnan knows that he and the musketeers will have no chance to rescue Madame Bonacieux if they attempt to fight the cardinal’s guards. Monsieur Bonacieux doesn’t like this plan, but he goes along with it, partially because he has no other choice.
Evidently, Monsieur Bonacieux’s attempts to shield himself from trouble have failed. Although Monsieur Bonacieux expects d’Artagnan to help him, d’Artagnan does not because he knows that doing so will only create more problems. This is a big step for d’Artagnan’s character and shows that he’s already matured since arriving in Paris. Previously, d’Artagnan couldn’t wait to get into a fight, but now he knows that fighting isn’t always the answer.
When the guards leave, Porthos chastises d’Artagnan for not fighting back. However, Aramis tells Porthos that he’s an idiot and that d’Artagnan was in the right. Athos congratulates d’Artagnan on his quick thinking as well. In response, d’Artagnan coins a motto for the group: “All for one, one for all.” After, the musketeers retire to their individual residences to rest up for their fight against the cardinal.
“All for one, one for all” is the most famous quote from the novel and is likely known even by those who’ve never read the story before. The meaning of the phrase is that d’Artagnan and his friends pledge to act for the good of the group. In return, the group will do its best to support its individual members.