The Haunted Civilization

Summary: a ghostly possession phenomenon accompanies an entire spacefaring species.

A man is working at a desk in a grassy field, near the edge of a forest.  There is a fence nearby stretching to the visible extent of the field - a long ways away, other things might be happening, but here he is isolated.  He's slowly packing his belongings back into a set of containers.  He's visited by the administrator of a school to which he's associated, and they have a short conversation.

Returning to the school headquarters, he overhears some discussion of a technical problem with a system he originated.  He speaks up, claiming that the problem can't be related to the work he did, and a man nearby agrees with him.

One of the administrators of the school disappears in the midst of his fellows.  It seems that he enters some sort of bizarre dream world, a sort of mockery of the school he is accustomed to.  When he returns, he is quizzed about his identity by suspicious comrades, who aren't sure if he's still the same person.  And he holds up one of his hands.  There is a large, perfectly round hole through the flesh, while the fingers are now short and stubbly to compensate for it.  It isn't damage per se, but his whole hand has been modified to accommodate having a hole in it.

A female humanoid anteater or some other sort of bizarre creature appears in a man's dream, hauling him away by the ankles.  He was sitting in a classroom; the fact that this creature was an anteater was not seen as unusual, but the whole affair seemed gossip-worthy to the students.

A physician is speaking to another man, a senior fellow of some sort of organization, and a woman is present.  Both are aware of another man, who is slowly undergoing a psychological breakdown.  The physician assures them that he can use a drug, derived from some sort of fish, to calm the man down.  There are brief scenes of this man, strapped to a gurney, being taken through a hospital.  The senior man and his wife, it seems, have been using word games and manipulation to keep the poor chap in working order, but it wasn't a stable arrangement.

At a power plant, alarms are going off.  "We feed and feed but it ever hungers," says one of the technicians.

The tenth Doctor is standing among crowds of people, looking with concern into a night sky.  He is standing among the people of a civilization who live on steel structures embedded into an asteroid belt, and the power station has been keeping the whole affair together.

The power station's supplies collapse; klaxons blare.  Evacuation orders are given.  Parts of the asteroid field and the iron civilization destroy each other; one particular rock with a cross-shaped piece of rotating metal spins through other chunks, destroying them like a rotor.

Watching this is the Doctor and select individuals rescued in his TARDIS, aboard an 'observation deck' - another room inside with 'windows', from which surrounding space can be seen.  One of them asks, "so how does this machine go?"  The Doctor shrugs winsomely.  The questioner continues with a stream of technical jargon, and he nods, looking considerably more impressed: "Yah, something like that."

Instruments on the control panel indicate that the Time Vortex has been traversed; the Doctor has carried these survivors into their race's future, past the turbulent times of resettlement and loss.

However, by this time, creatures which inhabit and possess the race have become a standard recurring problem: they are now freely able to affect physical transformations on their hosts (such as the hole in the hand earlier, but on a larger scale).