Nell and Eve are precocious teenagers living with their anti-establishment parents in the middle of a redwood forest. Their contact with the outside world is sporadic, so it takes them a while to realize that civilization is crumbling around them. Hegland is vague about the reasons--a far-off war, new strains of disease, terrorist attacks on US soil. (She wrote this in 1996, when all of this was less hackneyed.) But after a few seasons of this, the family is left without electricity, internet, telephones, mail, or gas. They are stranded in the woods, with nothing and no one to rely upon but themselves.
It sounds much more interesting than it is. The story is told through Nell's POV, and it would be hard to craft a generic character. Her sister Eve has a bit more personality, but that personality is so broadly drawn that it's hard to give much credit. Although the girls are alone with each other for most of the story, their relationship has only the trappings of intimacy, and none of the depth of it. This book has all the emotional intensity of a school essay--and reads like one, too.
OK, so the characters and emotional life are a bit lacking--surely their methods of survival would make up for it? Alas, no. Hegland is as vague about how to can or make acorn flour as she is on the intricacies of the girls' relationship. It's all very thinly sketched.
If you want to read about surviving amidst the ruins of Western civilization, I'd recommend reading how i live now or Parable of the Sower, or heck, even Hatchet before bothering with this. It's not a bad book--but it's not a good one.