Jan Chappell plays a dual role in this episode, as alien telepath Cally and as Cally's sister, Zelda. Receiving a mental message from Zelda, Cally learns of a deadly plague on her home planet, Auron. The person responsible for this calamity is Servalan (Jacqueline Pearce), who wants to get her hands on Auron's sophisticated cloning process. "Children of Auron" originally aired on February 18, 1980. ~ Hal Erickson, Rovi