Sydney Fox is a professor and globe-trotting "relic hunter" who looks for ancient artifacts to return to museums and/or the descendants of the original owner. She is aided by her linguistic assistant Nigel and occasionally by her somewhat air-headed secretary Claudia. She often ends up battling rival hunters seeking out artifacts for the money.

It's 1649: Mazarin hires the impoverished D'Artagnan to find the other musketeers: Cromwell has overthrown the English king, so Mazarin fears revolt, particularly from the popular Beaufort. Porthos, bored with riches and wanting a title, signs on, but Aramis, an abbé, and Athos, a brawler raising an intellectual son, assist Beaufort in secret. When they fail to halt Beaufort's escape from prison, the musketeers are expendable, and Mazarin sends them to London to rescue Charles I. They are also pursued by Justine, the avenging daughter of Milady de Winter, their enemy 20 years ago. They must escape England, avoid Justine, serve the Queen, and secure Beauford's political reforms.