In the Musketeers’ final adventure, D’Artagnan remains in the service of the corrupt King Louis XIV after the Three Musketeers have retired and gone their separate ways. Meanwhile, a mysterious prisoner in an iron mask wastes away deep inside the Bastille. When the destinies of king and prisoner converge, the Three Musketeers and D’Artagnan find themselves caught between conflicting loyalties.

It is a time of both splendor and despair for the deeply divided French nation where the self-serving King Louis XIV enjoys the riches of the world while his people starve. Believing he is all-powerful, Louis fears no one -- except the one person who could bring an end to his absolute power: the man he condemned to wear an iron mask and imprisoned for life. But when the king's selfish excesses go too far, retired Musketeers Athos, Porthos and Aramis...