“It is 4 March, 1215, and the TARDIS materialises in England during a jousting match held in the presence of King John.
But it soon becomes apparent to the Fifth Doctor that something is very seriously wrong. Why does John express no fear or surprise at the time-travellers’ sudden appearance, and indeed welcomes them as the King’s Demons?
And what is the true identity of Sir Giles, the King’s Champion?
Very soon the Doctor finds himself involved in a fiendish plot to alter the course of world history by one of his oldest and deadliest enemies.”
The King’s Demons was a novelisation based on the 1983 television serial The King’s Demons. At 153 pages, this adaptation of a two-episode story is ten pages longer than the novelisation of The War Games, which adapted a ten-episode story. [tardis.wikia.com]