In the first season, when the 100 arrived on Earth, they were supposed to be alone. We soon discovered they were not, and the Grounders joined the fun. Close to the end of season one, the Reapers appeared. The end of the season teased us with a new group, on top of the Ark survivors arriving on Earth.
And here we have the dystopian society that has gone through an end-of-humanity war and have become moles who live underground in a seemingly peaceful and cheerful society.
You know it's gonna end bad.
The idea of a new group, one that has kept its "civilization" but its probably hiding a darker secret than the Grounders is not an original one, and they show will have to tread with care not to become a caricature of itself. On the other hand, correctly done, it can add to the fun. In this first episode, it does, as it adds some interesting questions: how come they need people from over the ground, why are the interested in the people that came back from the Ark, what did they do with Anya...? Some of the 100 seem to like the change, to have a roof, food and be clean. Clarke, being smart, is not.
On the ground, Finn and Bellamy are having another kind of problem. The people from the Ark are back, in with it, both of them are losing their position of power and becoming "children" again. Kane is going to take control, but for how long and how is what the show will have to answer. Bellamy and Finn have been free for too long, and it's difficult to cage a wild animal. Talking of wild animals, Murphy is also alive. The show has used him as a bogeyman, but it seems more humanity will be infused to his character. Another bad that becomes I-really-had-a-messed-time-growing-up-but-I'm-good-deep- down? Let's see.
So many new plot developments, change of pace, and interesting new characters and situations make for a good start for season two.
