The young D'Artagnan arrives in Paris with dreams of becoming a king's musketeer. He meets and quarrels with three men, Athos, Porthos, and Aramis, each of whom challenges him to a duel. D'Artagnan finds out they are musketeers and is invited to join them in their efforts to oppose Cardinal Richelieu, who wishes to increase his already considerable power over the king. D'Artagnan must also juggle affairs with the charming Constance Bonacieux and the passionate Milady de Winter, a secret agent for the cardinal.