The Key to Time – Story 3
The Doctor and Romana arrive on 20th Century Earth to find the third segment of the Key to Time. The story involves a lot of silliness with witchcraft, a stone circle, stones that turn out to be intelligent life forms, an alien prison ship and more fun than seems reasonable. It was also the 100th Doctor Who story, and a good one too.
Extras include a documentary on the making of the story, a short item on the influence of horror movies on Doctor Who, and some other rather nice bits and pieces. Good stuff all round, really.