Twenty years after Aramis, Athos, Porthos, and d’Artagnan went their separate ways, the new cardinal, Mazarin, asks d’Artagnan to find his three friends and enlist them to help Mazarin during the Fronde civil war. Only Porthos accepts, and the four musketeers soon find themselves on opposite sides of the conflict. This cannot, of course, last very long, and they ultimately join forces in England to try to rescue Charles I from Cromwell. Along the way, they are discovered and pursued by the son of Milady, their diabolical female adversary from The Three Musketeers .

Though not as well known as the first installment, Twenty Years After continues the wit, charm, friendship, and most of all the adventures that Dumas made famous in The Three Musketeers .