After Cardinal Richelieu hears that the Queen has given the Duke of Buckingham a token of love, a diamond heart, which was a present from the King to her, he persuades the King to insist on the Queen wearing the jewel at a forthcoming gala. Comte de Rochefort and Lady de Winter are sent to London to recover the jewel and return it to Richelieu, who plans to produce it at the gala, thus revealing to King Louis his wife's treachery. Meanwhile, the Queen has sent Constance, her lady-in-waiting, to entreat the Musketeers to recover the jewel in time for her to wear it and confound her enemies. Trouble ensues when the evil D’Artagnan steals the jewels. After a hectic sword fight over, the Musketeers reclaim the jewels and bring them to the gala just in time to produce the jewel at King Louis' demand so that he may fasten it at the Queen's shoulder as he had done originally.