The inhabitants of one dark planet realised their civilisation was dying out. They experimented with Earth humans to find a way of preparing them for their world's conditions and way of life, so they could be brought 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. The Third Doctor investigated the college 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. (PROSE: The Dark Planet)