‘There are three physical gateways and the three are one.’ After the mystery of the first episode, this is much more down to earth. It provides some answers which, of course, only prompt more questions, but the overall sense is progress in unpicking the plot. The Gundan Robots are revealed to be the creations of a slave rebellion against an empire that once ruled all of known space, whose masters ‘descended out of the air riding the winds and took men as their prize, growing powerful on their stolen labours and their looted skills.’ There’s poetry in the script, which, combined with the fairytale setting of a long-abandoned feast, makes for a striking and compelling episode.

While the Doctor discovers the secrets of the gateway, Romana matches wits with Captain Rorvik and his crew. Their initial encounter, in which she tries to baffle them with non sequiturs and pretentious philosophising, almost feel like Gallagher is sending up artsy SF. Elsewhere her dialogue is much punchier, almost Moffattish:

ADRIC: Why believe Biroc?
ROMANA: Because he was running

Her capture and installation as a living component of what looks like a slave ship’s time drive is horrible. Similarly, the forced revival of the captive Tharil, which begins to rove through the starship like a beast in search of prey and provides a second memorable cliffhanger.

It’s made perhaps more horrible because Rorvik and the crew are such mundane villains – probably the most mundane the fourth Doctor has faced. They’re not galaxy-conquering megalomaniacs or planetary dictators or even local tyrants, just a bunch of profit-hungry mercenaries cornered and resorting to increasingly desperate measures. Some of them, like Kenneth Cope’s hapless Packard, are even quite funny. The science-fantasy majesty of the backdrop of fallen empires and long-ago wars comes up against the reality of ordinary people in space.

Next episode: Warriors’ Gate – Part Three