The Pertwee era continues to be strong and entertaining as we begin season 8. The first appearance of the Doctor's equal, The Master, played brilliantly by Delgado. The Autons aren't as good in this as they were in Spearhead, not as menacing or present. But, that's because they're just pawns for the Master. This is Jo Grant's first story as the companion, she goes on to be my favourite of Classic Who. Another UNIT regular starts here as well: Yates. A good story.