Getting Back — William Dietrich

In an overpopulated and polluted near future, every region of the earth has been explored, organized and tamed, except for one: the mysteriously empty continent of Australia. And Outback Adventure promises to catapult cubicle-dweller Daniel Dyson into the experience of a lifetime...without telling him there may be no return. Dyson and his fellow survivalists set out eagerly to test their mettle against the wilderness. But they don't realize that the game is rigged, and that the ultimate danger is not hunger or thirst, but their fellow human beings.