Spoiler alert: If you don't want to know any more about "Falling Skies" than what you may or may not have seen in commercials, stop reading now.
(CNN) -- American sci-fi fans are missing something.
After roughly 20 years on television, the "Stargate" franchise is defunct. The "Battlestar Galactica" franchise is still waiting to launch its latest iteration, "Blood and Chrome," and the resurrected "V" franchise, which ran on ABC, ended after two seasons.
Where are all the aliens on television?
This weekend, at least some aliens will be on TNT, as "Falling Skies" premieres Sunday at 9 p.m. ET. Robert Rodat and Steven Spielberg have been working on the show (an apocalyptic science fiction show about an alien invasion that decimates Earth's societies) for three years, and fans have been waiting.
(TNT, like CNN, is owned by parent company Time Warner.)
The "Falling Skies'" preview at last year's San Diego Comic Con sparked excitement from a packed room of fans, but series star Noah Wyle knows the stakes are high.
"I was amazed at the turnout we got," Wyle said. "And just how closely that particular audience pays attention to detail. How wounded they feel (after) being jilted in the past (by other science fiction shows) and so they have an apprehension about embracing a new project.
"But once that audience is won over, I don't think there's a more loyal following anywhere. They seem to be the most vociferous letter writers in the country to support shows they enjoy, and hopefully we'll be one of them," he said.
Sci-fi fans say they have been burned by TV in the past and are cautious with their excitement for shows like "Falling Skies" and FOX's upcoming "Terra Nova." Fledgling shows with ardent fan support have not been lucky in prime time in the last year.
"It seems like if a show doesn't come out of the gate blazing white hot and maintain that 'Wow' factor, they're gone in two episodes," sci-fi fan Shawn Hill said.
Hill, who works in the IT security industry, spent 13 hours getting a stargate tattooed around his elbow.
"I feel like American networks don't get it," said Joy Scarborough, an insurance agent in Athens, Georgia, and an avid science fiction fan.
Citing NBC's recent pass on "Seventeenth Precinct," a supernatural show created by "Battlestar Galactica" alum Ron Moore, which would have ostensibly been a cross between "Harry Potter" and "Law and Order," Scarborough said, "The networks are not catering to the people who want to see something intelligently written. I think they're absolutely missing out and BBC and Syfy get it."
In order to fill the programming void, plenty of fans who tuned in to long-established franchises are turning to "Doctor Who" on BBC America and "Eureka," "Haven," "Sanctuary" and "Warehouse 13" on the Syfy channel.
"Falling Skies" executive producer Darryl Frank knows what sci-fi fans have been missing and said it was a specific design of the show to get writers who could offer compelling stories.
"We literally had writers from 'Battlestar Galactica,' 'Lost,' 'Heroes' and for the second season, a writer from 'Stargate,' " Frank said.
"We specifically went out there to pursue people who could tell those types of stories. But then we also wanted to make sure the people that were tuning in weekly who didn't know about the mythology because maybe they missed a week or two could still get on for the ride," he said.
Mark Verheiden, a co-executive producer and writer for "Falling Skies" is one of those people. He's worked on "Battlestar Galactica," "Smallville" and "Heroes."
"One of the big differences I think with 'Falling Skies' from many other invasion shows is that we're actually starting six months after the main 'shock and awe' invasion has happened. So our survivors have had six months for the shock to fade and now they're faced with a series of choices. They're essentially under occupation from this alien force, which is very strange," Verheiden said.
The aliens are mysterious, he said, because they aren't talking or negotiating with the captive Earth population.
"These aren't the Cylons, who look like us and we can talk to and try to talk our way out of it or negotiate or something. These creatures are very complicated and strange."
Wyle admits the aliens seen in "Falling Skies" are "really freaky."
"We didn't have the benefit of knowing what they were going to look like when we shot the pilot," he said. Instead, the actors reacted to an image of one of the giant spiders from the movie "Eight Legged Freaks" that was blown up on a piece of cardboard and carried around by a prop guy.
Freaky aliens and end-of-the-world scenarios are often catnip to the sci-fi fan community, something executive producer Justin Falvey knows all too well.
"Something Steven (Spielberg) spoke about from the beginning is, it should feel incredibly authentic and incredibly grounded in real human emotions. People should be able to posit the question, 'What would you do if you were in this scenario?' " he said.
Apocalyptic science fiction uses out-of-this-world circumstances to describe human struggle, Falvey said The most interesting area for "Falling Skies" creators to explore was the human character, he said.
"Everything in terms of how we judge people in society -- socioeconomically, education-wise, all those things -- they go away immediately given what's happened here," he said.
It's one reason why science fiction fans love the genre so much. Stories that envision the future can focus on how society evolves and what fantastic technology could exist, like Gene Roddenberry's vision in "Star Trek," but they can also show a more directly relatable side of future humanity.
"Everyone pulls together for the good of all mankind" in apocalyptic science fiction, said Scarborough. "There's a lot more pulling together in science fiction than really any other genre."
"And you don't see that every day. With a tragedy you do, you see people pull together for a little while and it gives you hope that people do have that in them," she said.