We start off with a simple jar, placed in the Tennessee wilderness. We get a description of that jar, which seems maybe a little bigger than your average jar, but after all, it's still a jar. The surprising thing is that this jar seems to take over. The wilderness is ruled by the jar and seems no longer wild.
But still, the jar is out of place in Tennessee, and there are things that the wilderness can do, like grow and breed, that the jar can't.