John Marsden 
Tomorrow, When the War Began [EPUB ebook] 

When Ellie and six of her friends return home from a camping trip deep in the bush, they find things hideously wrong — their families gone, houses empty and abandoned, pets and stock dead. Gradually they begin to comprehend that their country has been invaded and everyone in the town has been taken prisoner. As the horrible reality of the situation becomes evident they have to make a life-and-death decision: to run back into the bush and hide, to give themselves up to be with their families, or to stay and try to fight. This reveting, tautly-drawn novel seems at times to be only a step away from today’s headlines.