Written by Terence Dudley and first telecast March 16, 1983, the conclusion of the two-part story "The King's Demons" finds the Doctor's old enemy, the Master (Anthony Ainley), attempting to alter the course of history (for the worst, of course). Hurtling himself back to the year 1215 A.D., the Master creates a shapeshifting robot to impersonate King John (Gerald Flood) at the signing of the Magna Carta -- while the Doctor (Peter Davison) races against time to prevent a disaster of far-reaching proportions. With "The King's Demons, Episode 2," Doctor Who wrapped up its 20th season on the air. ~ Hal Erickson, Rovi