At the end of the last story, The Sensorites, Ian had made a quip about The Doctor's piloting of the Tardis. The Doctor, annoyed by the quip, decides to return Ian and Barbara back to Earth. They do arrive on Earth, but instead of England in the 1960s, they arrive in the late 1700s in France during the height of the Reign of Terror.
While exploring a nearby farmhouse, the travelers are overtaken by a couple of counter-revolutionaries fleeing the French government. The Doctor is knocked out by the revolutionaries, but before anything else can happen, French soldiers lay siege to the house.
The two counter-revolutionaries are killed during the siege. Ian, Barbara and Susan are mistaken for fugitives and are taken to the Conciergerie prison, with the ultimate fate of being guillotined. Ian, however, is thrown into a cell with an Englishman named Webster. Webster reveals to Ian that there is an English spy, James Stirling, who has been holding an important position in the French government. Webster had been sent to tell Stirling that he is being recalled back to England. After Webster's death, a government official by the name of Lemaitre is eager to learn what Webster has spoken to Ian, but Ian remains tight-lipped and refuses to say anything. Lemaitre removes Ian from the execution list in hopes of learning what Ian has been told.
Meanwhile, The Doctor awakens after having been knocked out during the siege, having been rescued by a local boy from the farmhouse, after it had been set on fire by the French soldiers. The Doctor travels to Paris to rescue his companions. Once there, he impersonates a French official from one of the provinces. Lemaitre is suspicious of The Doctor, and uses several tricks to keep The Doctor in Paris while he attempts to learn The Doctor's true identity.
Barbara and Susan, meanwhile are rescued while being taken to the guillotine by a group of counter-revolutionaries led by Jules Renan. They are led to a safe house, where they can recover from the ordeal. Susan has been sickened by her stay in the prison, and a visit to a physicianis arranged. This visit proves disastrous, as one of Jules' compatriots, Leon Colbert, is found out to be a spy for the French government and Barbara and Susan are recaptured.
Ian, who had escaped the prison and met up with Barbara and Susan prior to their disastrous visit to the physician, also goes off to meet with Colbert. Colbert captures Ian and plans to torture him in hopes of learning the whereabouts of Stirling. Jules rescues Ian, and kill Colbert in the process.
The Doctor, meanwhile, has been forced to make a visit to Robespierre, the leader of the French government. The Doctor is to provide a report about the region he is supposedly responsible for. The Doctor is able to sidestep giving his report, but is ordered to return the following day. Upon his return to the prison, where The Doctor has been staying, he discovers Barbara and Susan. The Doctor is able to effect the release of Barbara, on the pretext that she can lead the French soldiers to the hideout of the counter-revolutionaries.
Lemaitre, however, discovers The Doctor's plans. He holds Susan as a hostage, and forces The Doctor to lead him to the counter-revolutionaries hideout. Once there, it is revealed that Lemaitre is, in fact, James Stirling. He has been ordered by Robespierre to spy on Paul Barras, Robespierre's deputy. Barras has a clandestine meeting planned at an inn outside of Paris. Ian and Barbara disguise themselves as innkeepers to discover who Barras is meeting. It should come as no surprise that Barras is meeting Napoleon Bonaparte (I saw this one coming from a mile away!).
Shortly after this meeting, Robespierre is deposed. While Robespierre is being led to the prison, Stirling keeps his word and has Susan released from prison. The Doctor and his companions leave Paris though the help of Jules and return to the Tardis to resume their travels.
Six episode stories in Doctor Who usually tend to feel a bit padded, like they're stretching not enough butter over a slice of bread. This isn't true with the Reign of Terror, however. It's such a complicated story that it's just as well that it is six episodes long.
I'd be remiss if I didn't mention the fact that the BBC has wonderfully animated the two missing episodes from this story. I personally think the animation is slightly better than the animation used for the Second Doctor adventure The Invasion, the other instance where this technique was used. Two more incomplete series will use this method to round out and complete their stories, The Tenth Planet (the final First Doctor story) and The Ice Warriors (a Second Doctor story). Both of these episodes will be released later this year, and I'm looking forward to both releases.
The Reign of Terror is a great finale to this first series/season. I'd rank it as my favorite serial from this series/season, even above the first and iconic Dalek story. It's well worth your time to check it out if you've never seen it.
