Heroes on the battlefield, the Musketeers return from the Spanish front to a Paris seething with resentment. Food shortages and profiteering have turned the poor into a powder keg about to explode. And, lurking in the shadows of the city, a dangerous new enemy threatens to light the fuse. The corrupt Governor Feron has been running Paris for his own ends, aided by the brutal Red Guard. As the King’s illegitimate half-brother, he has been twisted by a bitter sense of entitlement.

But behind Feron hides an even greater menace. Lucien Grimaud is a vicious gangster with a powerful hold over the governor. High taxes have turned the aristocratic establishment against a seemingly indifferent King, and Grimaud is conspiring to exploit the monarchy’s weakness. While Feron might be reasoned with, Grimaud deals only in chaos and rage.

Ordered to the heart of this simmering crisis, the Musketeers face their most treacherous test yet. It’s a task that will challenge their allegiances to the crown, throw their personal lives into turmoil and compromise their loyalty to those they love – and to each other.