In 17th century France, young D'Artagnan wants to join the King's Musketeers, but instead befriends three legendary musketeers—Athos, Porthos, and Aramis—and together, they become embroiled in the political intrigue surrounding King Louis XIII and his adversaries, particularly the powerful Cardinal Richelieu.

The Four Musketeers defend the queen and her dressmaker from Cardinal Richelieu and Milady de Winter.

It's 1649: Mazarin hires the impoverished D'Artagnan to find the other musketeers: Cromwell has overthrown the English king, so Mazarin fears revolt, particularly from the popular Beaufort. Porthos, bored with riches and wanting a title, signs on, but Aramis, an abbé, and Athos, a brawler raising an intellectual son, assist Beaufort in secret. When they fail to halt Beaufort's escape from prison, the musketeers are expendable, and Mazarin sends them to London to rescue Charles I. They are also pursued by Justine, the avenging daughter of Milady de Winter, their enemy 20 years ago. They must escape England, avoid Justine, serve the Queen, and secure Beauford's political reforms.