D'Artagnan (Michael York), a young swordsman, arrives in Paris with one dream: becoming a Musketeer. He meets and quarrels with Athos (Oliver Reed), Porthos (Frank Finlay), and Aramis (Richard Chamberlain), three Musketeers, who invite him to join them in fighting the evil Cardinal Richelieu (Charlton Heston), who wishes to extend the already considerable power he has over the king.