Aired April 7 - May 12, 1973
Written by: Terry Nation
Directed by: David Maloney
But the Doctor has already recovered, and upon meeting the Thals, learns that they were sent here on a secret mission to destroy a group of Daleks who are on Spiridon to attempt to discover and replicate the native Spiridons' invisibility.
Another Thal ship arrives, with a second group of Thals on board. They were sent after it was discovered that Spiridon is also home to a hidden army of ten thousand Daleks. The Doctor and the Thals discover that, in a cavern below the Dalek base, an army of thousands sit frozen in suspended animation, waiting for the moment to launch a massive offensive.
The Doctor and the Thals hatch a risky plan to detonate a bomb in the cavern, causing one of Spiridon's ice volcanoes to erupt, which will entrap the Dalek army within liquid ice. Successful, the Thals steal the Dalek ship to return home, stranding the remaining Daleks on Spiridon. The Doctor and Jo head back to the TARDIS, and embark on their next adventure.
After eight years away from the programme, Terry Nation returns to Doctor Who and to his famous creations, the Daleks. In the late 1960s, Nation had been working hard to try and get an American Dalek series off the ground, but had found no success. The creatures did make him a very wealthy man, but ironically they were only successful as part of the series on which they spawned, and the stories in which they appeared were always among Doctor Who's most popular. So, each needed the other, and Nation was glad to see them back on the show. However, he had conditions, and a big one was that he be the writer to provide scripts. He had always had qualms about the David Whitaker-penned stories of the Troughton era, and he wanted to once again be in control of his creations.
So it's very, very odd that, after so long away and so much time to come up with new and original plots and concepts, the story we get here is a virtual re-tread of numerous plot elements from his earlier stories. The Daleks again plan to unleash a bacterial weapon. The planet has deadly plants that pose a threat to our heroes. The story is a series of escapes and traps, with the heroes splitting into two groups with different missions, just like in The Daleks. The themes of courage vs inaction are just a slight alteration of the pacifism vs resistance themes of the first Dalek serial. It's put together like a game of mad-libs.
The scope of the story is nice, with the threat of invisible Daleks intriguing, though never capitalized on. The Spiridons could have been compelling and interesting, but we only get to know one of them, and the concept of the all-over fun-fur shrouds is a fairly obvious work-around of not being able to make their invisibility work. So, are they naked most of the time, but then have to put on these giant furs at night to avoid freezing to death? Because that, from an evolutionary point of view, is ridiculous.
The Thals are mostly interesting, though their internal conflict is just boring. There's some nice performances, particularly from the always good Bernard Horsfall, and the understated and subtle relationship between him and Jane How's Rebec is nice. Katy Manning gets lots to do as Jo, and at this point it's such a nice thing that her character has been allowed to grow and develop tot he point where she can carry the action for long stretches and have agency and intelligence and bravery. The Jo of Season 8 wouldn't have been as effective as she is here. Manning and the writers both have deepened and developed her in a believable way.
This isn't the worst story of the era, and though I'd never call it good, it at least holds your interest. It's got a number of exciting set pieces, and the performances are all good. It's good to see a Dalek story that manages to disguise how few Daleks they actually have so effectively. There are other aspects of the production side that are pretty woeful, none more so than how badly the Supreme Dalek is operated, and I certainly wouldn't call this anywhere close to David Maloney's best work (in fact it might be his worst), but I was never bored. It's just a regurgitation of things we've seen too many times at this, all of them done better elsewhere.
Also, it's really weird that this story, supposedly a continuation of the events of Frontier in Space, really has almost nothing to do with that much, much better story. Barry Letts should have been chuckled at for even suggesting that the preceding story and this one form one 12 part story, and one of the most annoying things is how big an opportunity was missed to craft one long single narrative. It would have had to have been better than what we wind up with.