Dr. M got this book free at the end of one of his teaching classes, and while I don't usually like to start a series in the middle, I wanted to put the book in my "sell" pile* and just couldn't let myself do that until I'd read it. It's really kind of a compulsion.
I didn't know until I started exploring things that A Killing Frost (1995) (originally titled The Third Day, The Frost) is the third book in Australian author John Marsden's extremely popular Tomorrow Series.
In the first book in the series, Ellie Linton (our narrator), a rural Australian teenager, and six of her friends go camping in the bush outside of their small town. When they get back, they quickly notice that there are no people around and all the farm animals are starving. After finding a warning from her father, Ellie and the other teens learn that the country was invaded by a foreign army (never named in the book) who wants to imprison the Australians and colonize the country. They go back into hiding and end up fighting a guerrilla war against the invaders, with their actions building up and becoming more and more ambitious.
By the time we get to this third book, some of the group is dead and some are imprisoned. Ellie and the remaining friends are extremely bored in hiding and decide to walk to the big regional port, which is being used by the enemy to bring in people and weapons. They come up with a plan to attack the port, but at great risk to themselves. And if they survive the explosion, they realize the enemy won't be able to ignore them any longer.
While I almost certainly would have enjoyed this book more if I had read the first two books in the series, Marsden gives enough background that the book works reasonably well on its own. Motivations and emotions are sometimes spelled out a little too clearly, and sometimes the characters and dialogue are pretty broad, but I think that can be forgiven in a young adult book. The action and suspense scenes are very well written and make the book hard to put down -- I can see why the series has been such a success with young readers. I didn't like the book enough to seek out the rest of the books in the series (which was initially supposed to be a trilogy, but ended up having seven books plus a follow-up series called The Ellie Chronicles), but if one landed in my lap I'd probably give it a read.
[* holy shit, I just looked the trade paperback version that I have of this up on Amazon and its going for at least 50 bucks! Mayhaps I will get lucky...]