The story starts in Paris in April 1794, year II of the French Revolution. Theresia Cabarrus is a beautiful but shallow Spaniard who is betrothed to Citizen Tallien the popular Representative in the Convention and one of Robespierre's inner circle. She is credited with exercising a mellowing influence over Tallien, whom she met in Bordeaux but although she is engaged to be married to him, what little love she has appears to be lavished on another.

Bertrand Moncrif is a good-looking but impulsive young man who appears determined to martyr himself in opposition to the revolutionary government. To this end, he has gathered the siblings of his long-term sweetheart, Régine de Serval, into his plan to denounce Robespierre at one of the Fraternal suppers. Despite warnings from Régine he insists on carrying through his plans which inevitably go awry and the wrath of the mob is soon turned towards the small group. After a timely intervention on the part of the Scarlet Pimpernel, using the guise of the coal heaver Rateau (who also appears in several short stories in The League of the Scarlet Pimpernel - The Cabaret de la Liberté, Needs Must and A Battle of Wits), the de Servals are saved from a lynching while Moncrif lies unconscious and unseen under a table.