The Elystrians lived in a peaceful and perfect society. The planet was called the Planet of Paradise. To make the lives of his people even more enjoyable, Vayla created robots to perform menial tasks. The robots overthrew their creator and imprisoned him. They killed most of the Elystrians. A few managed to survive and went into hiding. They held meeting in which they discussed possible courses of action.
One day, the Fourth Doctor, Adric and K9 arrived on the planet. K9 saved the life of Sklar, scaring away his robot pursuer. Sklar showed them to their hideout, used for meetings. The Doctor agreed to help free them. He asked about Vayla's position and the people were under the impression that he still controlled the robots and was responsible for the attacks.
Entering the stronghold, the Doctor managed to free Vayla while the others staged a distraction. Adric used a co-ordination control, stolen from the robots, to deactivate them. As the Elystrians had kept records of their society with which to rebuild it once they won back their planet, and they presumably did. (PROSE: Planet of Paradise)