Raoul de Bragelonne, son of Athos, is intent on serving France and winning the heart of Louise de la Valliere. D'Artagnan, meanwhile, is perplexed by a mysterious stranger, and soon he learns that his old comrades already have great projects in hand. Athos seeks the restoration of Charles II, while Aramis, with Porthos in tow, has a secret plan involving a masked prisoner and the fortification of the island of Belle-Ile. D'Artagnan finds a thread leading him to the French court, the banks of the Tyne, the beaches of Holland, and the dunes of Brittany.