The Knight of Maison Rouge is the story of what happens when two people from opposite political camps fall in love during Robespierre's reign of terror.

Paris, 1793. Lieutenant Maurice Lindey is an ardent young republican who hates tyranny and injustice whether they come from the left or right. But such even-handedness is a liability at a time when addressing someone as "monsieur" instead of "citizen" can bring one to the guillotine. Maurice makes daily visits to his love, Geneviève Dixmer, who lives in a quarter known as the hiding place of the Chevalier of Maison Rouge, a daring counterrevolutionary with notorious plans to free Marie Antoinette, who languishes in prison awaiting trial and inevitable execution. Soon Lindey is drawn in to the plot by the queen's champion.