In 1793, the terror of the French Revolution is at its height, and the guillotines are busy. But a mysterious figure is staging daring rescues, and Citizen Chauvelin, the head of the Central Committee of Surveillance, is determined to discover his true identity, and uses a number of informants, including the popular actress Minette Roland.

The Pimpernel is called upon to track down Helene, the daughter of the Marquis de Rochambeau. However, Chauvelin is also looking for her, and so is Gabrielle Damiens, the head of the local revolutionary regime. Sooner or later, their paths are bound to cross.

The Dauphin is being held prisoner by the Republicans. When he is captured by a masked intruder, Robespierre orders Chauvelin to find the boy before news gets out.