The Light of Dawn by Steven Ruiz

The last inhabitants of a ruined world are either citizens of the State, a government led by the despotic James family, or the wards, independent settlements whose denizens struggle with virtually no support from the State. Julie Kingsale is an engineer from Diamond Ward who has worked tirelessly to support her neighbors since she was twelve years old. When Julie wakes in an unfamiliar room with no memory of how she got there, a strange man tells her that they are being hunted and need to escape.

The stranger is Ben Piedras, a State police officer who was recently expelled to the wards for a murder he claims not to have committed. Though he and Julie are both killed in their effort to escape, they are returned to the strange room unscathed. Their escape is one of many trials which they must work together to overcome. Each time they fail, they must begin again, with only Julie retaining memories of their failures.

Outside the mysterious trials, Julie learns that a neighboring ward, once desolate, is now thriving due to the support of a mysterious group known only as Dawn. Desperate to help the people of Diamond Ward, she appeals to Dawn. Meanwhile, Ben attempts to survive in the downtrodden Prophets Ward by leading a fledgling constabulary. When his life is threatened, he violates the terms of his expulsion by fleeing the ward. Intrigued by tales of a mysterious cult settling in Diamond Ward, Ben makes his way there.

Ben and Julie must work together to escape their predicament, learn more about Dawn, and do what is necessary to bring prosperity to the people of the wards.