Marguerite and Percy love each other very much, but circumstances put walls between them. She has caused a nobleman to be executed, while, unbeknownst to her, he has been trying to rescue aristocrats from the French guillotine. Both she and he must fully reveal themselves to each other, or their love will die.

Shortly after they marry, Marguerite tells Percy about her part in the arrest and killing of the Marquis de St Cyr. Pride, however, prevents her from giving all the details, especially that she had meant only to cause distress to the marquis for having her brother beaten and that revolutionary conspirators had tricked her into coming forward for their own lethal purposes. After some months of Percy’s rejection, and her sarcastic reaction to it, she begs him to forgive her, but his pride prevents him from doing so.

At the same time, the French agent Chauvelin forces her to help him discover the identity of the Scarlet Pimpernel, or he’ll order her brother executed for treason. She’s caught in a terrible dilemma: No matter how she chooses, one man must die.

Marguerite discovers that Percy is the Scarlet Pimpernel; the resolution of her dilemma takes on a terrible new urgency.