In Renaissance Paris, D'Artagnan (Michael York) is a young swordsman sent by his father to seek a commission in the King's Musketeers. After making the acquaintance of Musketeers Athos (Oliver Reed), Porthos (Frank Finlay), and Aramis (Richard Chamberlain), he soon finds himself enmeshed in a web of intrigue as Cardinal Richeleu (Charlton Heston) has his subordinates Rochefort (Christopher Lee) and Lady de Winter (Faye Dunaway) kidnap seamstress Constance de Bonacieux (Racquel Welch) to get proof that the Queen has secretly been having an affair with England's Duke of Buckingham (Simon Ward).