In my opinion Doctor Who reached its peak with season 13 - and this was the best of the lot. The pace and excitement never lets up throughout the six episodes and the performances are some of the best in the series history. Tom Baker and Elizabeth Sladen are at the peak of their powers here. The location filming is beautiful as is the incidental music. Also drected by the greatest Doctor Who director, Douglas Camfield and written by "Terror of the Zygons" writer, Robert Banks Stewart - both in their final DW outings. I cannot criticise this story, and even love the Krynoid. To cap it all, it has some of the best cliffhangers ever seen as well.