Young swordsman d'Artagnan arrives in Paris seeking the man responsible for killing his father – a quest that brings him into conflict with one of the king's guards. But as he quickly discovers, when you take on one Musketeer, you take on them all. It's soon back to business when the swashbuckling heroes are ordered to find a missing soldier who was carrying important letters on behalf of King Louis, while the dastardly Cardinal Richelieu plots to increase his political power.

Aramis helps an old friend to uncover the truth behind a disastrous mission.