We were wolves

The boy lives in a caravan on his own in the woods. His dad, John, is in prison and promises to get out soon. All the boy needs to do is survive alone for a little while longer. But dark forces are circling - like the bad man he's been warned about, who arrives asking questions; and the rucksack the boy must keep hidden; and maybe, just maybe, more ancient forces that have lain asleep for an age.