An alien cactus on a desert planet disguises itself as the Doctor and tries to steal a dodecahedron from a neighbouring planet and blow it up. I mean, what?! It’s the sort of ‘out-there’ idea that Doctor Who throws at you every now and again. It’s great to watch Tom Baker play the role of the bad guy as well, particularly all made up with spikes sticking out of his face and hands, and there are some pretty good visuals too (including some impressive motion controlled ‘bluescreen’), but beyond that the story is a let down.
It’s not terrible or boring or anything, but there are a few too many clichés, like another crew of idiotic bandits, or K-9 blasting open another door with his laser, or the chanting religious cult performing a sacrificial ceremony (again!). The story plays with the idea of a culture that wants to study this great power source that it relies on, with a subset who wish to simply worship it as a god, and the tensions that spring up between the two, but there’s little exploration of the themes of faith versus reasoning. In fact, very little is learned about the dodecahedron at all, other than it is very old, very powerful and can be used as a weapon of mass destruction. The priestess dies in an attack, so she never has to live in a world where her god does not exist.
Lots of little things like that are glossed over quickly. The jungle planet of Tigella is one minute lethal to its inhabitants, and in the last two minutes it’s suddenly a rich source of all their needs and everything will be fine! And the time loop that Meglos was able to create in the Tardis… erm, how? Is he the last of a race of time-travelling cacti or his knowledge of temporal engineering specific to him? The poor Earthling whose body he inhabits, where the hell did he come from (well, Earth, obviously)? And so on, and so forth.
A noteworthy bit of casting is Jacqueline Hill as the priestess Lexa, who previously played one of the first companions Barbara from way back in the beginning. Going from a rational teacher to a zealous cultist is certainly a change from one extreme to another, but it was nice to see her again.