The Doctor and Mel arrive at Paradise Towers after Mel decides, having seen a promotional video, that she would like to make use of their rooftop swimming pool, as the Doctor had jettisoned the TARDIS's pool as it was leaking!
The tower block represents a microcosm of a dystopian society, there are fractured groups of humans; the Kangs, girl gangs that clash with each other based on the colours they wear (red, blue & yellow), the Caretakers, jobsworths, who oversee the running of Paradise Towers cleaning the graffiti and acting as police, and the Rezzies, the older residents who rarely leave their apartments.
Not long after they arrive, the Doctor and Mel are taken prisoner by the red Kangs, who are planning to take out the remaining blue Kangs, having learnt that the last yellow Kang has been killed.
As is usually the case (if you watch enough Doctor Who) the Doctor and Mel get separated, and Mel winds up being invited into an apartment by Tilda and Tabby (Elizabeth Spriggs & Brenda Bruce), two (seemingly) harmless old dears who invite her in for tea and cakes.
It transpires that all of the able bodied men have gone off to fight in a war, leaving these disperate groups to look out for themselves, there is, it would seem, one heroic man left behind called Pex who appoints himself Mel's guardian and protector.
Something is lurking in the shadows in the basement, and one by one, the rezzies, kangs and caretakers are being picked of by the cleaners, a bunch of maintenance robots, who are being controlled by something or someone.
The chief caretaker (Richard Briers), is beginning to realise that he is no longer in complete control of what goes on in the tower block, and the Doctor soon realises that he has been allowing the cleaners to kill off people, in order to feed his "pet" in the basement, but that they are now killing in greater numbers, and the creature seems to be taking control, and it seems that it won't be satisfied until all the humans in Paradise Towers are dead.
This is an entertaining story, the writer, Stephen Wyatt, was inspired by J G Ballard's novel High Rise. The ideas are very good, but I'm not sure the execution of them always works. The cleaners aren't particularly scary, and they seem to struggle in their murderous duties!
And the robot that attacks Mel in the swimming pool is far from being sinister, and is rather cute!
The DVD has a reasonable number of extras including a documentary hosted by Mark Ayres on the making of Paradise Towers, Girls! Girls! Girls! The 1980s, a chat with Sarah Sutton, Janet Fielding and Sophie Aldred about being in Doctor Who in the '80s, deleted and extended scenes, and the opportunity to watch the programme with the original score which was subsequently changed to a score by Keff McCulloch at a very late stage.