The last The 100 show I watched was over a year ago. The ship had a bunch of volunteers quarantined off and slowly dying due to lack of oxygen. The teens on earth received some signal from the ship, but then were attacked by mutants or something. I think maybe the ship received some signal from earth and some were considering restoring oxygen supply to the volunteer suicides. A girl was captured by a mutant. What has happened since then?
Got to the second season, its just good enough to keep watching in the background.
It is clear the writers don’t even understand WHAT radiation IS, a character is told they metabolize it better than others…WHAT?
I’ve decided to let this all go and assume it is a case of the characters themselves being misinformed, and the entire show is a study in fear of “contamination” by the “other”.
Ark residents fear the ground irrationally, Mt. Weather people irrationally fear the outside and the grounders etc.
Although I guess it could be yet revealed that Mt.Weather leadership is intentionally misleading their population about the risk of contamination, which would be a good twist.
LOL midway through season 2 and oh my, I mean I don’t know if I can keep watching seriously.
This isn’t just a crapsack world, the characters behave irrationally to make it even more crapsack. They make characters behave radically irrationally for conflict, everytime someone behaves rationally and for mutual benefit they are instantly killed.
One wonders why Mt. Weather couldn’t TRADE for blood donations from the grounders or Ark people, that would be too rational for this show.
Shows about trade negotiations don’t go so well 
At least a mention of trying would help.
Man the best way I can describe this show is there are really good parts mixed in with really bad parts. The characters are all over the damn place, single episodes will feature triple crosses by people, it is almost too kinetic and the characters badly written.
Thought the latest ep I watched started off good and logical, then we got a CG giant carnivorous! gorilla never seen before. OK!
EDIT:Considering they are outright murdering hundreds of grounders, why did Mt.Weather never think to get some damn semen or eggs from them and start breeding the grounder DNA into their population? They just love being evil I guess.
There aren’t any mutants, except that two headed deer that they kept showing in all the promos before the series started.
So much has happened since what you last saw (the end of season 1 and all of season 2) that it’d pretty hard to try and catch you up in a message board post.
There is also a unseen giant aquatic snake? Alligator? in the pilot, and a giant meat eating gorilla.
We have seen some people with serious birth defects, that boy in the dead zone for example.