Anxious to obtain some crystals necessary to activate the Liberator's weaponry, Avon (Paul Darrow) enters into a slightly unsavory arrangement with criminal leader Bayban the Beserker (Colin Baker). In exchange for Bayban's assistance, Vila (Michael Keating) must use his lock-picking skills to open up a fourth-dimensional space portal. The plot thickens when Vila falls in love with Bayban's henchperson, Kerril (Carol Hawkins). "City at the Edge of the World" first aired on February 11, 1980. ~ Hal Erickson, Rovi