Steven Spielberg launched two science fiction TV shows last year — in a time when science fiction seems to be a third rail of television. One was Terra Nova, a show about time travel and dinosaurs. The other was Falling Skies, a show about alien invasion and post-humans. There are two huge differences between these shows: One of them is dead. And the other one is worth watching.

As it goes into its second season, Falling Skies takes the Spielberg ethos forward, and shows genuine promise of becoming something worth taking seriously. It's still not a perfect show, but it's good and getting better. Here are a bunch of reasons why you should give Falling Skies another shot on Sunday. With basically no spoilers for season two.

The comparison to Terra Nova is pretty instructive: both shows are focused on one family, with a dad who's the second-in-command to the leader of a small, struggling community. The main thing is, Terra Nova never really committed to its premise, and wasted our time with a lot of "amnesia virus" episodes. You never felt like the people of Terra Nova were facing any hardships, and despite a lot of sentimentality, the characters never seemed to have any real emotional connection to each other.

Meanwhile, Falling Skies has done a fair to decent job of selling the notion that the last human survivors of an alien invasion are in rough shape. And partly thanks to shorter seasons, the show has had a certain amount of discipline about sticking to telling stories that actually reinforce the set-up. And, last but not least, I feel like I know the Mason family. I feel as though the relationships among Tom Mason and his three sons are well-defined, and the show does a good job of making me believe in its main characters.

Season one of Falling Skies definitely had some teething problems — including a few too many "inspirational" Hallmark Channel moments. To be clear, I was never objecting to genuine emotion on this show. But schmaltz isn't real emotion, it's manufactured sentiment. As the first season went on, I got the sense that the writers were leaning more on the actual relationships between the characters, and less on scenes where random people mouth greeting-card sentiments to each other. And that trend definitely continues in season two — in the first few episodes, there are plenty of intense emotional moments, and even a montage or two. But the action never stops dead so that a minor character can say something that's the equivalent of a "Hang in There" kitten poster.

As our interviews with the show's cast and creators show, the second season sees the resistance fighters in much direr straits, and there's a lot less room for coziness this time around. This show has to walk a bit of a tightrope to be successful — they can't have aliens attacking every five minutes, both for budgetary reasons and because that would actually be quite boring. But you need to have a sense that the aliens could attack at any moment, or at least a sustained sense of menace. And at least in the first few episodes, the show does maintain the feeling of a group of resistance fighters on the run and hemmed in by enemy troops.

And meanwhile, the central metaphor of the show continues to be posthumanity. How does living with aliens change people? Most obviously, there's Ben Mason, who was the aliens' slave and still bears the marks of his captivity on his spine. But the question of whether Ben is still human, and whether he's changing into a new form of life, is in many ways a metaphor for what's going on with everybody else on this show. Nobody is the person they used to be, and the longer they're surrounded by alien technology and influences, the more people are being transformed at a very basic level. It makes knowing whom to trust that much harder.

Falling Skies isn't the first alien-invasion story to turn into a post-apocalyptic story, by any means. But its "Jericho meets Independence Day" setup offers a rich vein of family drama and character-based action. Plus if you think about it, shows like Jericho are always about the nature of society — what do we owe to each other, when the chips are down? When society collapses, what do you try to hang onto? How do you rebuild social institutions?, etc. — and stories about humans fighting aliens are inevitably about the nature of humanity itself.

When you combine those two explorations, what makes us human and what brings us together, you get into some pretty challenging territory — and it feels like Falling Skies season two is fumbling towards exploring both things at once, largely through the lens of Ben and one or two other characters. One of the things that keeps me watching a TV show is caring about the characters (and I do actually care about the Masons) but another big thing is feeling like the show has a thematic mission statement — something Falling Skies season two does seem to have.

And then there's the elephant in the spaceship... Season one ended with an out-of-nowhere cliffhanger, that was up there with "four randomly selected characters are Cylons, and Starbuck is alive." Tom Mason had just (somewhat improbably) inflicted +5 damage on the mysterious alien structure in Boston, and as he and Captain Weaver were driving back to base, they encountered an alien ship, whose denizens invited Tom aboard. And he willingly clambered aboard the ship, which zoomed off. When we were doing interviews about the show in May, everybody was pretty up-front that this twist caught them off guard — including the new showrunner.

The good news is, this turn of events does more or less pay off in season two. If you can get past the idea that Tom would willingly choose to go hang out with the aliens he's been fighting for months (I guess, because he was worried about his son Ben and they promised him some answers) then at least the situation does lead to some interesting ramifications later on. And the whole question of "how does Tom get off the alien ship in one piece" is dealt with about as well as you could hope. The main thing is, you don't get the feeling that this show has painted itself into a permanent corner.

I get the impression that a lot of people gave up on the show during season one, or didn't like the latter half of the season as much as I did. I felt as though season one of Falling Skies started out sort of weak, and then found its feet later on — but I've talked to plenty of people who felt the other way around, that the first season got weaker as it went along. If you didn't like the second half of the first season as much as I did, then it's certainly possible that you may not like the start of season two as much as I did, either.

But if you gave up on Falling Skies early on, because you felt like it was too syrupy and not hard-hitting enough, or because you didn't feel persuaded by its depiction of life after an alien invasion, then you should consider giving the show another chance. The show's characters have gotten a lot sharper, and the alien conquerors of Earth are pleasingly ruthless this time around. And this show seems to have found a few rich thematic veins to explore, which I'm intrigued to see it delve into further.

One last thought: We're heading into the election season, when plenty of people will be debating (one way or another) the nature of a good society, and exactly what we, collectively, should be doing for each other. There will be plenty of sneaky indirect attempts to imply that someone else is less human than "we" are. So we should be delighted to have a show on the air that actually explores questions of who gets to be considered human, and what a society that's in terrible straits really ought to value.

Falling Skies season two starts this Sunday at 9 PM.