Part one of the two-part "The King's Demons" originally aired March 15, 1983. Written by Terence Dudley, this
Doctor Who adventure finds the TARDIS materializing on earth in the year 1215 A.D. -- or to be more precise, the day before King John (Gerald Flood) is to sign the Magna Carta. The Doctor (Peter Davison) doesn't know it yet, but he will soon be forced into another confrontation with his old enemy, the Master (Anthony Ainley). And that is hardly the worst of it -- as the Doctor will discover in the conclusion of this pulse-pounding adventure. ~ Hal Erickson, All Movie Guide