Our son constantly surprises us with the things that he finds frightening. These primitives, about whom we’ll be learning much in subsequent episodes, are the top of the list right this minute. He doesn’t see them as extras in camouflaged body stockings and plastic faces at all. They are unknown, silent, hideous and unreasoning. He was pretty pleased by the Doctor leading the colonists on a revolt to seize control of the IMC ship – the colonists don’t know that an adjudicator from Earth is due to arrive very soon to settle the problem – but Jo being taken to the primitives’ secret city is utterly horrifying. What are these creatures and what are they going to do? We’ll learn more in a few nights’ time!