The repeated COVID pandemics and the years of trouble that followed have ravaged Australia, leaving the country fractured and society in retreat. In Melbourne, economic troubles and an ongoing fear of even more dangerous strains of the virus have led to increasing isolationism with tighter governmental control.

When the government announced new movement restrictions, Dan and his family seized what might be their last chance to escape the city and the shrinking territory of Victoria that surrounds it. Their initial adventures are described in Beyond the Western Margin, and now in this sequel, Dan and his family rejoice as another happy camp draws to an end at Roses Gap, their home beyond the western margin. But when a camper, Ben, gets hurt, Dan hears enough to wonder if it really was an accident.

Meeting Ben after church in Stawell, it soon becomes clear that his "accident" was not just isolated bullying, but part of a much, much bigger problem.

Taking a few weeks off, the Turners travel to Moora Moora Reservoir and camp in the serene shadows of the dam wall, taking Ben with them for his safety. But Dan discovers that parts of the normally quiet valley are swarming with people, threatening greater danger than he could ever have imagined.

Terrorists plan attacks in the Grampians and further afield, and there's no time to waste: explosives have already been placed at their first target.

Can Dan and his family prevent a catastrophe, or is too late?