This was Tom Baker's second outing as the Doctor and he'd clearly got up to speed.
The Doctor, Sarah Jane Smith and Harry Sullivan find themselves on an apparently deserted space station. While the Doctor and Harry are trying to outwit the station's defence systems, Sarah Jane is teleported away to be prepared for deep freeze. The Doctor and Harry search the station looking for the missing Sarah and stumble upon its true purpose; a cryogenic storage place for the remnants of humanity after earth had been destroyed by solar flare activity. This gave the Doctor one of his best ever speeches in extolling the virtues of Homo Sapiens. but there's a bug in the system, and it's a damned big one. Here the designers verged on the borders of disbelief as infected humans are woken only to start transforming into insects with the aid of green painted bubble wrap. Rather surprisingly, it isn't that bad, though, as the horror of the transformation overcomes that initial disbelief - largely down to the ability of the actors involved of course.
The Space Station is a bit ropey by today's standards, but as one of the DVD options, you can have an updated version, though it's not much of an improvement.The fully transformed wirrn are also a bit iffy, especially when making their way through space.