Season six kicks off "The Dominators", which see the TARDIS arrive on the peaceful planet Dulkis, a planet the Doctor has visited before. A small group of the pacifist Dulcians are being forced into slave labor by two Dominators who have arrived in a spaceship along with their robotic servants, the Quarks. The Doctor intercepts the atomic seed and plants it aboard the Dominators' ship as it leaves, destroying it, while the volcano erupts harmlessly. Or nearly harmlessly, for the TARDIS is right in the path of the lava flow...