In the conclusion of the four-part story "Time-Flight," the renegade Time Lord the Master (Anthony Ainley) has split the alien Xeraphin in two halves, one good, one evil. Fortunately, the "good" half aligns itself with the Doctor (Peter Davison), who fully intends to thwart the Master's latest scheme to take over the universe. The Doctor also hopes to pilot a stolen Concorde jet from 140 million B.C. to contemporary London! Written by Peter Grimwade, "Time-Flight, Episode 4" was first telecast March 30, 1982, as the final episode of Dr. Who's 19th season. ~ Hal Erickson, Rovi