Materialising in a forest, the Doctor and friends find themselves 12 kilometres from Paris. It is the 18th century, and France is the scene of an ongoing battle between royalists and revolutionaries. Following a blaze at a farmhouse, Ian, Barbara, and Susan are separated from the Doctor and arrested as traitors. Ian receives information about James Stirling, an English spy vital to the revolution. No one seems to know where Stirling is, and locating him becomes Ian's priority.

The Doctor, meanwhile, arrives in Paris in the guise of a Regional Officer, and before long has an audience with Robespierre. With Robespierre's downfall imminent, and the revolution about to reach its climax, the Doctor and his friends must get away before they become victims of Madame Guillotine.

The remastered soundtrack of a classic story starring William Hartnell, with linking narration by Carole Ann Ford, who played Susan in these six episodes from 1964.