Determined to fulfill his dream of becoming a musketeer, D'Artagnan leaves home with only an old horse and a letter of recommendation to the Captain of the King's Musketeers. Although the letter is stolen, he quickly proves himself worthy and joins the ranks of Athos, Porthos and Aramis. The four become fast friends and band together to protect the King of France from the devious Cardinal Richilieu who plans to overthrow the monarchy.