While travelling through N-Space, the Doctor (
Tom Baker) and Adric (Matthew Waterhouse) find that a visitor has materialized on the TARDIS: the Keeper (Denis Carey) of the Union of Traken. Hovering between life and death, the Keeper must transfer his power to another, lest the Union be dissolved and evil emerge triumphant. Written by Johnny Byrne, episode one of the four-part
Doctor Who adventure "The Keeper of Traken" originally aired on January 31, 1981. ~ Hal Erickson, All Movie Guide