In When the Sun Goes Down, the entire world has been taken out in an unspoken incident, except two small districts nestled inside a canyon, living exclusively from the rest of the world. Without closer investigation, one might consider them blessed for surviving such a disaster, but the people of the Poor District are thankful for nothing. Instead, they seek solitude and act cruelly to anyone who crosses their path. It seems that Allison Frey and her best friend, Maverick, are the only two who are able to see the good in things. And Ally is the only one who is remotely interested in their past. She wants nothing more than the opportunity to learn. If no one else is going to try to change things, she will have to do it on her own.
As an eerie answer to her deepest wish, a powerful man from the Rich District sets his sights on her while traveling through town on one of his secret trips, and he collects her to live with him in his mansion. Of course, Ally cannot turn down such an amazing shot at what she's always wanted; especially considering the man is mysteriously handsome.
Leaving behind everyone she loves, she enters into a new life, one that's better than her old one in extremely unfair ways. The rich people don't have to fend off beast attacks and they live as if they know nothing of the Poor Districts struggles. As Ally adjusts to this district and a man who isn't at all whom she'd thought, she finds that the knowledge she acquires is the real danger.