Demeter was a planet located near Bellus. It was inhabited by an advanced humanoid race which suffered frequent attacks from the robots on Bellus. While preparing for the next attack, their world was visited by the First Doctor, John and Gillian in the TARDIS. Encountering the time travellers, who convinced them of their peaceful intentions, the people of Demeter welcomed them to their world.
During a banquet an attack from Bellus was launched. After helping evacuate the building, the Doctor returned to the TARDIS, where he activated the tremulator, which deflected the destructive waves from Bellus back to that planet, destroying it. In gratitude, the leader of Demeter presented the Doctor with a large, ancient jewel, and the travellers departed. (COMIC: The Ordeals of Demeter)