The Liverpool to New York undersea tube is basically a large pneumatic tube. Built at the end of the 20th century, it has been up and running for three years when one of the tube's engineers confides to a friend that it is not safe. The friend is leaving for Europe in the tube the next day. When disaster strikes, there is only one survivor to tell the story.
Out of nowhere came these grim, cold, black-clad men, to kidnap three Earth people and carry them to a weird and terrible world where a man could be a giant at will.
The sun has died, as have the stars. Not a solitary light shines in the heavens. The days of light are nothing by a legend -- they are a story told to soothe children. The last millions of humans still live in their Last Redoubt -- but the end of their days is at hand.
It has been ordained that a select few must from time to time pass over the threshold that divides a mortal's present life from the future. Written well over a century ago, John Uri Lloyd was a visionary who spoke of far distant worlds, dead civilizations, other dimensions and in particular, a world few of us will ever get to visit. A world hidden beneath our feet inside the earth.