The 100 was intense in season 2, but they are preparing to up the action going into season 3. Mount Weather was one of the most intense story lines in the series so far. It had the gruesome acts that the people of Mount Weather were willing to go to to survive and the ultimate mass genocide that Clarke and Bellamy have to live with after having killed everyone in Mount Weather to save their own people.
Add to that the betrayal by Lexa at Mount Weather and Clarke finds herself with very little trust in anyone and seeking isolation after what she did to survive Mount Weather. When we last saw Clarke she left Camp Jaha and was wondering on her own, though the writers have said she will find Lexa again and just what that means we don’t yet know.
The other former ark-people are still not on board that some grounders are good and some are not. To them all the grounders are the same, and that presents an issue for Bellamy and is ability to be a leader in Camp Jaha with his sister being a member of the grounders now. The question of whether war can be avoided is not an easy one but based on the extended trailer below, war is about to break out across earth and Jaha might just have the instrument of everyones destruction along with him.