Preppers, bags at the ready!!
This is a very curious tale, unsettling for the ambiguity Macpherson creates by pulling his two main characters out of society, and thus, never finding out what on earth is going on in the wider world.
The book was written in the 1930s, so the second world war was a threat, but it hadn't happened yet. Although Macpherson sets it in his future of the 1940s. Hugh, and (I'm assuming) wife Terry, live in Scotland. They were kids during the first world war, and saw how badly the COs were treated. So as war approaches now, they, as pacifists, want nothing to do with it, but with Hugh's draft arriving, they are frightened of what might happen to him. And so they pack up their gear and flee into the mountains to furnish a cave home at a site they'd found on previous wanderings, and try to live off the land. This is hampered by the fact that they need to remain unseen, firstly so that they're not rounded up for the draft, and secondly, so they're not attacked by the ongoing war that comes to the mountains (although who the two sides are and what they are fighting over remains completely unknown). They have to figure out how to live in the hard mountain environment, with the cold approaching winter, the hoards of midges and horseflies in the late summer, hunting for meat, not getting enough greens or dairy, and all the other complications. As many other dystopian writers discussed, they also see the issue between hiding out for a year or so - doable - or for the rest of their lives, which essentially means they can't rely on looting for certain supplies of food or tools. In that case you have to be able to make or grow everything you need.
There is a creeping uncertainty as to what is going on in the wider world. They go back to their house as Terry is feeling sentimental, only to find it completely trashed. Hugh goes to a farm one time to steal some turnips, to find it also trashed and abandoned. Sheep are left unsheared on the mountains much later than usual. Gun battles are heard in the distance. They have no idea what has happened.
And it seems no man can be an island, because they decide, after helping a dying, starving soldier, that they need to rejoin the human race and help people where they can. Perhaps naively strolling down the hills, and getting shot for their troubles.
The descriptions of the land and the account of these two people setting up their secret home in the mountains is so detailed as to make you think Macpherson actually trialed it out. I think the sense of the land is the best part of the book for me.