LogFAQs > #975097693

Also if you want to see this exact plot done well, watch the two part storyline The Zygon Invasion/The Zygon Inversion from series 9 of Doctor Who. Its literally a paranoid sci-fi spy thriller about an alien race of shapeshifters integrating into the population without public knowledge where they take the place of people by putting them in pods and the main villain is an extremist faction that wants to start a war. Those episodes are great (with an incredible Peter Capaldi performance) and cover much more ground with a fraction of the budget and time.