This is the second story in a row that evokes Terry Nation’s Survivors, though even more keenly than what went before. Christopher H. Bidmead is in surprisingly good form covering the adventures of this last band of humans on the edge of the universe. This civilization is under attack for years by an enemy they have been unable to see. The leadership are unduly suspicious of The Doctor despite his offers to help their ailing people. Perhaps it’s unsurprising that some are deeply cynical in this harsh environment.

You work out fairly quickly who is really running the show and trying to stop this group of survivors from being able to find out the truth. It’s great seeing Davison have some substantial dialogue to deal with. He rarely gets lines this good. Turlough has far more than usual to deal with too, manically overwhelmed, entranced with ancestral memories of what the Tractators did to his people (nice that he isn’t basically treated like a human character for once!)

The big drawback, and one that gets more important the further you get through, is that the Tractators don’t look that great, but in fairness they blend into the surroundings well and their looks fit well with the story. Their motivation and gravitational powers are well thought out.

The punchiness of the script does lose some of its way in the final act but I enjoy how the conclusion comes together. The Gravis’ is tricked into using its powers to restore the wrecked TARDIS. The repurposed and changed TARDIS set looks amazing - iconic!

Incidentally it’s funny how Bidmead decides that 21 years into this show The Doctor and his companions should finally start worrying about what the Time Lord’s would do if they found out they were messing with events…! I’ll let it go though after what was easily his best script. A fitting final engagement with the show. (Lets ignore The Hollows of Time).