Dark planet

Dark planets were worlds which received almost no light, but were capable of supporting life as radioactive minerals produced heat. The inhabitants of one dark planet, realising that their civilisation was dying out, experimented with Earth Humans to find a way of preparing them for their world's conditions and way of life so they could come to their world and perpetuate their civilisation. One experiment, on the inhabitants of a Swiss village in 1777, resulted in their deaths. In the 1970s, they influenced the founding of Sayle College to prepare the students and teachers for this. The Doctor arrived at the college to investigate, and learned the plan from Clifford Leane. This experiment failed when a fire burned down the college, but the Doctor suspected that the aliens might try again. (DWA: The Dark Planet)