With the Liberator's energy sources low, the crew is forced to lock into the orbit of a desolate planet. It soon turns out that this "dead" world is actually a gladiatorial arena for two hostile alien powers. Blake (Gareth Thomas) and Jenna (Sally Knyvette) are forced to square off against Travis (Stephen Greif) and his pilot in a grim duel to the death -- and woe betide Blake's crew if he happens to be the loser. A collaboration between two longtime Doctor Who associates (writer Terry Nation and director Pennant Roberts), "Duel" first aired on February 20, 1978. ~ Hal Erickson, Rovi