Greg Rich is beginning to get the hang of things in 1615 Paris. Having assumed the identity of a young D'Artagnan, Greg united the legendary three Musketeers and succeeded in freeing his parents from a dank prison cell. But he hasn't figured out how to get home. Or how to defeat the dangerous Michel Dinicoeur. When Dinicoeur escapes from the Bastille and flees to Spain, the Musketeers charge through the French countryside in hot pursuit. The boys are unexpectedly joined by Milady de Winter and her friend Catherine. Along the way, the group is ambushed by knife-wielding thieves and assassins. Someone is anticipating their every move. But who? And how? There appears to be a traitor in their ranks, and if the Musketeers can't trust each other, who can they trust? It's "All for one, and one for all!"... Isn't it?