5Z4 - Castrovalva 4

It was an interesting decision to produce the debut Fifth Doctor story fourth in production order. It's not as if Peter Davison wasn't a skilled enough actor to be able to portray a new Doctor in his first story, despite the almost total lack of direction given to him by his superiors in the Doctor Who production office. (It fell upon a small child talking to Davison on a chat show in 1981 to suggest that Davison should play his new Doctor "like Tristan, but brave".)

Looking ahead, Davison's performances over his first four stories don't signify any drastic learning curve in regards to his character (with the possible exception of some scenes in Four To Doomsday), but if Davison finding his feet led to him giving the performance he does in Castrovalva, then all the better for it. Some of my favourite little Davison moments occur in this story, particularly the moment where he heroically bellows "We've got to find out what's causing the occlusion. Follow me!", before immediately collapsing on his bed and uttering, in slight panic, "Please find the zero cabinet."

Castrovalva provided a few of these scenes for The Doctor to stretch his wings a bit and show the range of the character, but not as many as would be expected for a regeneration story. However, this is the first story that deals with, and in fact devotes an entire story to, the various problems that can occur with regeneration, something that every subsequent regeneration story would deal with, to lesser or greater effect.

Above all, though, Castrovalva, amidst all the hangover of math-happy plot contrivances from writer Christopher H. Bidmead that he couldn't cram into Logopolis, is particularly memorable story, mostly for what was in it as opposed to what it was about.