Nissa is in a tribe of Grounders. Murphy is from the Sky People. The Grounders hate the Sky People. The Sky People hate the Grounders. On both sides there are many deaths. On both sides there is so much hate. When Murphy gets taken by the Grounders in hoping of learning the Sky People's weakness, he meets Nissa. Nissa is kind to Murphy, and Murphy can't help developing feelings for the compassionate Grounder. Both of them know they can never be together, but both of them also know that they care for each other too much to not be.