Writing credits
Alexandre Dumas père  (novel)
George MacDonald Fraser
 

Cast overview, first billed only: 
Oliver Reed ....  Athos  
Raquel Welch ....  Constance de Bonancieux  
Richard Chamberlain ....  Aramis  
Michael York ....  D'Artagnan  
Frank Finlay ....  Porthos/O'Reilly  
Christopher Lee ....  Rochefort  
Geraldine Chaplin ....  Anna of Austria  
Jean-Pierre Cassel ....  Louis XIII  
Spike Milligan ....  M. Bonancieux  
Roy Kinnear ....  Planchet  
Georges Wilson ....  Treville  
Simon Ward  ....  Duke of Buckingham  
Faye Dunaway ....  Milady de Winter  
Charlton Heston ....  Cardinal Richelieu  
Joss Ackland ....  D'Artagnan's Father  
  

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.