The 100
So. 97 years ago, humans killed the planet via nuclear war making it totally inhospitable on account of the radiation but that's okay because twelve (formerly thirteen but one, quote, "fell out of the sky") countries had inhabited space stations in orbit. Those space stations then came together to form The Ark and everyone just hung around waiting for the radiation to disperse and the Earth to be safe again. Except the oxygen systems on The Ark are dying three years ahead of schedule. Solution? Send down a hundred (hence the name of the show) juvenile delinquents (the only kind of criminals the Ark has seeing as how they just chuck adult offenders out the doors and into space) wearing vital-monitoring wristbands to see if they can survive on the surface. Because there's no way anything could possibly go wrong with that plan.
Needless to say, pretty much everything goes wrong with that plan but that's okay because, hey, remember how the Ark's failing? Sooner, rather than later, they just bring the whole Ark crashing down to Earth because a maybe-death totally beats a definite death by oxygen deprivation. And of course, "Our kids are down there!" *eye-roll*
Oh? And the 100? They survive which is, you know, nice and all. Except for the two that died in their dropship's crash landing. And the Chancellor's son (he was such a sweetheart - a real noble guy) who was killed by a little girl with a bit of a brain-break. And said little girl who hops off a cliff. And that was BEFORE they realized that, hey, humans actually did survive on the surface. Sure they're a little savage, a little primitive, a little...Native American gone Rambo, but it's somewhat comforting to know that even nuclear fallout couldn't kill off the human race. Take that, cockroaches!
Naturally, of course, the not-quite-100-anymore end up engaged in guerilla warfare with the Grounders who on their part mistook the Sky People for invaders. Of course, when the 100 sent up flares trying to tell the Ark they were alive and accidentally burnt down a Grounder village, combined with when they captured a Grounder they then proceded to torture, it's not hard to see how the Grounders came away with the Sky People = Bad opinion. They may have been on to something.
Of course, you can't have a CW show without a love triangle. I swear they actually have this written in their contracts or something. So. Finn was a "rebel" - a goofball who wasted three months of The Ark's oxygen so he could go on a spacewalk. Then Wells (the aforementioned Chancellor's son who was all good and noble) died and Finn took over as the resident Jiminy Cricket. Clarke, the daughter of a councilwoman who also happens to be The Ark's top medic and the engineer who first discovered the impending Ark failiure (Spoiler! it was a discovery did not end well for him), is the sort-of-kind-of-but-not-really co-leader of their rag-tag bunch of miscreants. Basically, she has medical knowledge thanks to her mom and comes from one of the more well-to-do families thanks to her mom's position plus she's got inside scoop thanks to her dad so, apparently, that all adds up to leadership. Sort of. Raven (who was NOT one of the 100 - she came later in her very own one-man drop pod) is The Ark's number one mechanic and something of a techno-wizard (because every rag-tag bunch of miscreants needs a weapons master!). Finn and Raven dated on The Ark. He went to Earth, met Clarke, built a bond with her...and then the day after he sleeps with her, Raven lands on Earth. Awkward doesn't begin to cover it.
And then there's the family drama...
The Ark, for obvious reasons, institutes a strict one child law. Above? That's Bellamy and his little sister Octavia. Clearly their mother disregarded the one child law...which, sixteen years later when Octavia was found out, resulted in Mom being tossed into space and Octavia being locked up as a criminal. When Bellamy was told about the plan to drop the 100 down to Earth, he made a deal to get himself on board as well so that he could look out for his little sister. Which went swell...until a regrettable sibling squabble during which Bellamy told her that his life had ended the day she was born. Ouch.
Needless to say this led to Octavia storming off on her own. Which in turn led to her falling down a hill. Think the Man in Black's "As...you...wish!" tumble but with a rock to the forehead at the end. This, of course, led to:
Remember the Grounder that the 100 captured and tortured? Meet Lincoln. He'd been watching them since they'd landed and had something of a crush on Octavia. So, naturally, when damsel met distress he rescued her, tended to her wounds, did what he could to protect her brother's search party when they ran afoul of his people, and had his efforts rewarded by said damsel flipping out and knocking him unconscious when he tried to chain her up for her own protection (protip: girl who has spent her whole life in one cage or another does not do well with potential returns to captivity). Of course, then came the whole captured-by-her-brother-and-tortured thing.
Bright side for him, Octavia rescued him by drugging everyone in camp and slipping him out while they were all high and having visions. Which, naturally, led to this:
It's very Romeo and Juliet.
Oh, and Season 2? Turns out that of course the Earth is freaking radioactive - it's just that the Grounders, who've lived on the surfuce since forever, and the Sky People, who were in space and thus minus the atmosphere's protection against solar radiatioin, have adapted with time and their bodies are now able to filter out the radiation.
Also, Romeo's a cannibalistic savage (briefly), the love triangle abruptly ends, and turns out the Grounders are good people. And it's only been 8 episodes.