I'll admit it: I was a kid when this was repeated for the Silver Jubilee
celebrations in 1988, and I watched parts of it through the crack in the door
from the kitchen. (My little brother could never be frightened by anything not
in colour, but not so me.) This is one of the few stories that still grips and
frightens me as an adult, if in new ways. Fewsham's dilemma is real to me in a
way it never was for my younger self. The vulnerability of the Earth and the way
that new and near-ubiquitous technology can make us more vulnerable to attack or
disaster and not less hit home in a way they never could for a child. This isn't
just bug-eyed monster stuff, this is actual sci-fi.
There's innovative camera work here which is very effective. The Doctor is
written out for an episode (actor's holiday) in a way that works so well you
mightn't notice. The guest cast are mostly spot-on. Women are allowed to get
things done instead of merely being rescued all the time. The bad guys have a
plan that makes sense, and motivations you can believe in. And the story
presents a threat to Earth you can genuinely believe ordinary people would give
their lives to stop.
This looks beautiful on DVD, and the special features are moderately
interesting. As always with a story of this length (it's a 6-parter) you'll
notice some padding, but on the whole the pacing's excellent and this is a real
gem of the Second Doctor Era. I'd consider it the essential Second Doctor DVD
purchase, actually, ahead of Tomb of the Cybermen. Highly recommended, and
accessible to new viewers.
This story has been re-released more recently in one of the Revisitations box
sets, with extra special features, so consider buying that set instead if you're
interested in the other stories it contains.