Erak was out on patrol with Zake when they spotted the Fourth Doctor. Erak returned to camp and told Krans, before returning to the scene. They found the Doctor by the body of Zake and blamed him for the death. After seeing Roth, Erak ran off to chase him and when he returned, found the Doctor had gone. Erak, Krans and Vural found him climbing out of a crevice but were captured by a robot and taken to Styre. There, Erak and Krans were forced to lift a gravity bar above Vural while Styre increased its weight. The Fourth Doctor distracted Styre while Sarah Jane Smith and Harry Sullivan freed them. After Styre's death, Krans and Erak — the only survivors — decided to head for the Nerva Beacon. (TV: The Sontaran Experiment)