This serial stands out for several reasons. Fans know it as the one in which Sarah Jane Smith is introduced and that alone is worth a viewing. The character starts off unlike any other assistant. In this second episode she even believes the Doctor to be the villain. A second plus is the historical background. It seems as if it takes some pressure off the producers to come up with an alien world and gives them a chance to put more emphasis on story and character. (Without too much scientific mumbo jumbo it is also easier to follow.) Designer Keith Cheetham created a very realistic, dirty Middle Ages, his only ever job for Doctor Who. It's a pity we never saw him do an alien world.
Of course it still remains a children's programme. Sarah Jane adapts to the strange world very easily, without any trauma, and the enemies in the Middle Ages all seem to be living in castles, a stone's throw apart.