This is one of the storylines I would have seen bits of pieces of when it was originally broadcast back in 1984 without really following what was going on.
Revisiting it after more than 25 years I note three things:
One, the production values are probably worse than I remember. The underground dragon creature is a particular low point.
Two, it's quite a good little story with a fair amount of "which faction is working for who?" going on. There's Scottish gunrunners, soldiers, androids impersonating soldiers, a substance that gives eternal youth, political blackmail and assassination.
Three, Nicola Bryant as companion Peri is gorgeous. I dare say I am influenced by the 13 or 14 year old version of myself. But she is.
Early in the first episode she and the Doctor get stung by some webby alien egg thing they find in a cave. It turns out they have caught a bad case of "spectrox toxaemia" and poor Peri gets weaker and progressively more wheezy as the episodes progress. Meanwhile one of the the villains, the masked Sharaz Jek, captures Peri and wants to spend eternity gazing on her beauty. Fair enough.
|"Peri, I don't fancy yours much."|