Doctor Who: Purgatory 12

Set during season 18's “E-Space trilogy”, this sees Adric's sulkiness trap the TARDIS crew on a habitable asteroid used as a penal colony. The result is something of a mixed bag.

The story itself isn't bad, and there are some inventive ideas to do with the bizarre ecology of the asteroid - something that's presumably only possible because E-space doesn't conform to the same laws of physics as our universe. This does, incidentally, appear to be deliberate; for instance, a link is drawn to what's happening here and the fact that the night sky in E-Space is green, not black. On the other hand, it does mean that a lot of the setup is left unexplained and this extends to the nature of the villain, which remains an enigma throughout. Similarly, we have no idea who has established the penal colony, or what any of the inmates are supposed to have done to get sent there (relatively little, so far as one can tell from the only hint given, but who knows?)

While Romana also gets plenty to do, aside from the Doctor, it's Adric and K9 who end up most notable here. The former alternates between arrogant and sulky which, in fairness, isn't a bad rendition of the way he was shown on TV and his resulting actions do at least help drive the plot. There's also an attempt to rehabilitate him, reminding us of what he went through in Full Circle and showing him start to bond with the other regulars in a way that was glossed over in the original TV series. K9, for his part, gets to flirt with another computer, insofar as such a thing is possible, which is a fun use of the character.

So, a decent use of all the characters, a plot that at least keeps moving and has some good ideas... but a lot will depend on whether you want any kind of explanation as to what's really going on. 3.5 stars.