You know, Turlough supposedly has a racial memory of the Tractators, and I don’t know if racial memory is a real thing or not, but it sure did come in handy here.
The other thing that comes in handy is the Doctor introducing himself to the Tractator leader, the Gravis. He’s different. He can talk, and he wants to talk to the Doctor. See, Gravis has some plans and hopes the Doctor will be amenable to at least looking the other way. Can’t have the Time Lords interfering after all!
The Time Lords don’t do that sort of thing. But the Gravis doesn’t know that.
As it is, the Doctor is able to use this plan of being friendly to save young Plantagenet. It mostly works. Turlough shows up with the Security Dick and some other guys, and Security Dick sacrifices himself so the Doctor and the others can escape. Tegan gets separated from the others but then finds…the TARDIS’s inner walls?
She also finds the Gravis, but she manages to get away. By then, the Doctor knows what to do. Turlough’s racial memory tells the Doctor that the Tractators by themselves are rather harmless as long as the Gravis isn’t around, and Plantagenet knows about the whole “turn the planet Frontios into a spaceship” plan. So, the Doctor figures out a plan. See, Tegan got away from the Gravis by going through a door and finding the TARDIS’s console room where the Doctor and the two men already were waiting for her.
After that, it’s actually rather easy. They let the Gravis back in and explain that this is the TARDIS, but the Tractator gravity powers left it a mess. The Gravis wants to go to other worlds, so he puts the TARDIS back together with his own gravity powers, and then the Doctor turns the TARDIS on and takes the Gravis away from the others. Since the Gravis by itself can’t do much of anything, it shuts down, and the Doctor takes it to a distant planet by itself where it won’t hurt anybody except maybe the rocks that make up everything on that world.
Say, what does a Gravis eat anyway? Asking for a friend.
From there, the Doctor can take the recovered Plantagenet back to the colony, giving the colonists the gift of the hat rack before he and his two companions leave again. But the TARDIS is acting up, dragging them all to the center of the universe.
That sounds bad.
Anyway, next up is a two parter that says hello to the Daleks and goodbye to Tegan.