This might have had a touch more menace to it, had the eponymous creatures bent on Earth's conquest not looked like the famous yellow-coats at a seaside holiday camp. Anyway, they are the chosen implements of the malevolent "Master" (Roger Delgado). He has returned to assist the powerful "Nestene" with their dastardly plans but hasn't counted on the intervention of the "Doctor" (Jon Pertwee) and his UNIT ally the "Brigadier" (Nicholas Courtney) who are intrigued when a secret power unit is stolen; then a radio telescope is put out of action and bodies start popping up all over Britain seemingly the victims of suffocation. Now it's up to our intrepid Time Lord to piece together the pieces of this puzzle before humanity is cling-filmed to death. It's good to have "Capt. Yates" (Richard Franklin) back to complete the military team and this story gives "Jo" (Katy Manning) a little more of a role as she proves invaluable helping the "Doctor" work to thwart their antagonists. Thing is, though, despite the best efforts of Delgado - and his penetrating stare - as the megalomaniacal mastermind of evil, this is just another rather cheap and cheerful drama that comes across as vaguely comical at times, and has way too much script. There's just not enough happening, and though the premiss that the world might regret being quite so dependent on plastic one day has some resonance, there's just no peril here and the flat denouement rather sums it all up. I'm sure budgets were an issue, even in 1971, but I think the "Doctor" needs to get back into space and give us some baddies we can get to grips with rather than yet another series of episodes that focus too much on saving our own planet - again, and again whilst facing the endless red-tape of the British government.