As a young boy, d'Artagnan witnesses the murder of his parents at the hands of Febre (Tim Roth), chief henchman of Cardinal Richelieu (Stephen Rea). d'Artagnan is nearly killed after using his dead father's sword to fight Febre which leaves him with a permanent scar and blinds him in one eye. d'Artagnan is taken in by family friend Planchet (Jean-Pierre Castaldi), a former musketeer, one of the loyal protectors of King Louis XIII (Daniel Mesguich).
The story takes place during the 17th century in the Spanish Empire. Diego Alatriste is a soldier in the service of King Philip IV of Spain, during the Eighty Years War. The story begins in the Netherlands, where the tercio of Diego Alatriste fights against the Dutch during the Dutch Revolt. Lope Balboa (father of Íñigo and friend of the captain) is killed here. Diego decides to return to Madrid where he receives the young Íñigo Balboa in his care.
The young d'Artagnan arrives in Paris with dreams of becoming a king's musketeer. Quite unused to the city life, he makes a number of clumsy faux-pas. First he finds himself insulted, knocked out and robbed by the Comte de Rochefort, an agent of Cardinal Richelieu, and once in Paris comes into conflict with three musketeers, Athos, Porthos, and Aramis, each of whom challenges him to a duel for some accidental insult or embarrassment. As the first of these duels is about to begin, Jussac arrives with five additional swordsmen of Cardinal Richelieu's guards. D'Artagnan sides with the musketeers in the ensuing street fight and becomes their ally in opposition to the Cardinal, who wishes to increase his already considerable power over the king. D'Artagnan also begins an affair with his landlord's wife, Constance Bonacieux, who is the Queen's dressmaker.
A swashbuckling swordsman is tricked into enlisting into the army of Louis XV in the mistaken belief that he will therefore be allowed to marry one of the King's daughters.
Richard the Lionheart (Norman Wooland), King of England, vanishes while returning from the Crusades. One of his knights, the Saxon Wilfred of Ivanhoe (Robert Taylor), searches tirelessly for him, finally finding him being held for ransom by Leopold of Austria for the enormous sum of 150,000 marks of silver. Richard’s treacherous brother, Prince John (Guy Rolfe), knows about it, but enjoys ruling in his absence.
In 1668 Jamaica, Morgan Adams hunts down her uncle and fellow pirate Dawg Brown, who has captured her father, Black Harry. Black Harry has one of three pieces of a map to a huge stash of gold on the remote Cutthroat Island. Dawg has another piece, having stolen it from the corpse of a third brother, Richard, while a fourth brother, Mordechai, has the last piece. Harry refuses to give Dawg his piece and escapes with Morgan's help, but not before being mortally wounded. A dying Harry reveals to his daughter the location of the map piece: on his scalp.
During a war between France and the Protestant rebels of La Rochelle, Cardinal Richelieu orders Count de Rochefort to kidnap Constance Bonancieux. The evil Milady de Winter, who wants revenge on d'Artagnan, seduces him to keep him occupied. D'Artagnan soon discovers her true nature, however, and also that she was once married to Athos, who had supposedly killed her after discovering that she was a branded criminal.
D'Artagnan (Gene Kelly), an inexperienced Gascon youth, travels to Paris to join the elite King's Musketeers. On his way, he encounters a mysterious lady at a roadside inn. When he picks a fight with one of her escorts, she becomes suspicious and has him knocked unconscious. His letter of introduction from his father to de Treville (Reginald Owen), the commander of the Musketeers, is burned. When he awakens, he continues on to the city.
In France just prior to the French Revolution, Queen Marie Antoinette (Nina Foch) asks her cousin Noel, the Marquis de Maynes (Mel Ferrer), to uncover the identity of "Marcus Brutus", a dangerous pamphleteer rousing hatred of the aristocracy.
After England and Spain make peace, notorious pirate Henry Morgan (Laird Cregar) decides to reform. As a reward, he is made Governor of Jamaica, with a mandate to rid the Caribbean of his former comrades, by persuasion or force if necessary. He replaces the former governor, Lord Denby (George Zucco), but is not trusted by either the lawful residents or the pirates.
Set in an indeterminate year of the 1840s, the film opens in a villa in Madrid, Spain, where Don Diego Vega (George Hamilton), the archetypal Spanish Don Juan, is in bed with a beautiful woman who, we learn shortly, is not his wife, but someone else's. The couple are caught by her husband, Garcia, who "is not in Barcelona", as they had previously thought. Diego, with considerable panache, fights Garcia and his five brothers with swords. During the fight, Diego's mute servant Paco (Donovan Scott) reads a letter (via gestures) from Diego's father requesting that Diego return to California [then a part of Mexico]. Diego and Paco escape by jumping from a high wall directly into a waiting carriage.
In 1191, Richard the Lionheart (Ian Hunter), the King of England, is taken captive by Leopold V, Duke of Austria while returning from the Third Crusade. Richard’s treacherous brother Prince John (Claude Rains) usurps the throne and proceeds to oppress the Saxons, raising taxes supposedly to pay Richard's ransom, but in reality to secure his own position.
In the time of Frederick Barbarossa, in the area of Italy known as Lombardy, Dardo Bartoli (Lancaster) is walking with his son Rudi (Gordon Gebert) when they encounter Count Ulrich (Frank Allenby), known as "the Hawk", together with his niece, Lady Anne (Mayo), and his lover, Dardo's unfaithful wife Francesca (Lynn Baggett). Dardo shows off his skill as an archer by shooting down Ulrich's expensive hunting hawk. In revenge, the count takes Dardo's son to his castle. Dardo is struck by an arrow while rescuing Rudi, so the boy allows himself to be recaptured in order to draw the soldiers away.