After some sudden and unspecified catastrophe has depopulated England, the countryside reverts to nature, and the few survivors to a quasi-medieval way of life. The first part, The Relapse into Barbarism, is the account by some later historian of the fall of civilisation and its consequences, with a loving description of nature reclaiming England. The second part, Wild England, is an adventure set many years later in the wild landscape and society.
Consider the poor mailman of the future. To "sleet and snow and dead of night"--things that must not keep him from his appointed rounds--will be added, sub-zero void, meteors, and planets that won't stay put. Maybe he'll decide that for six cents an ounce it just ain't worth it.
"Nothing could be done. The thing was universal and beyond our human knowledge or control. It was death for young and old, for weak and strong, for rich and poor, without hope or possibility of escape." Must Professor George Challenger and friends, barricaded in a room, see Earth die? As globe passes through a belt of poisonous ether, terror sweeps mankind; cities riot; communications cease