The TARDIS travellers, thinking they are returning to 20th Century England at last, arrive near 18th Century Paris during the French Revolution. They take shelter in an abandoned farmhouse, but it turns out to be a staging house for counter-revolutionaries. First, they are attacked by the counter-revolutionaries, The Doctor knocked unconscious, the others held at gunpoint. Then soldiers surround the house, kill the counter-revolutionaries, set fire to the house, and drag Susan Ian, and Barbara away. The Doctor is saved from the fire by a young boy who tells him the others will be in the Conciergerie Prison in Paris, and The Doctor sets out to find them.
The prisoners are sentenced to be guillotined. In prison they become involved with English spies. In Paris, The Doctor talks a tailor into providing him with the uniform of a Regional Officer of the Provinces, in which guise he meets Maximillien Robespierre. Ian escapes, Susan and Barbara are rescued from the tumbrel taking them to the guillotine. After a round of adventures, captures, escapes and revelations of duplicity, there is finally a coup against Robespierre, and everyone is glad that freedom will be theirs now that General Napoleon Bonaparte is in charge.
The story was well received, though it was criticized for historical inaccuracies, like pretty much every historical movie ever made, and like a lot of six-part Who adventures, it got a bit tedious in the middle after an exciting beginning. The last two of those episodes were wiped from the BBC archives. For the VHS and DVD release, these were replaced with fairly decent animation using the surviving audio.
William Hartnell was at his best bamboozling the tailor into believing The Doctor was a powerful figure in the revolutionary government and making expensive clothing for him for no money whatsoever. This is when we begin to realize that The Doctor is a con man as well as a curmudgeon and it only makes us love him all the more. Later Doctors, particularly Tom Baker and Matt Smith, took this revelation and ran with it.