It's 1793 and the Reign of Terror is slicing through the elite of Paris - but not if the Scarlet Pimpernel has anything to do with it! With a very British pluck, and daring bravado, he rescues French aristocrats from Madame Guillotine's embrace. But who hides beneath the Pimpernel’s mask? And isn’t the Scarlet Pimpernel just a fictional character?

At Highmoor House, in England, Peri plays lady of the manor while the Doctor tends to the strange wounds of her ‘husband’, Sir Percy Blakeney. As Peri prepares to host a lavish ball in Sir Percy’s name, French agent Citizen Donat, and a sinister alien force are uninvited guests, both intent on unmasking the Scarlet Pimpernel and putting an end to his heroic escapades, forever!