Clarence Rimbro owns the complete planet Earth. That is no great accomplishment as, a large number of years inside our future, anyone can do it. There are thousands of possible Earths, each existing in its parallel universe. If the opportunity of life arising on anybody of them is approximately 50%, then half enough time a random selection of a parallel universe will bring about a dead Earth. Since there are always a trillion persons surviving in this time, it will be almost impossible to allow them to go on one Earth, so each family creates its house and garden, protected by a force field and running on solar powered energy, on a dead Earth. Clarence enjoys total independence for his family, and a whole planet’s worth of liveable space. As you may still find thousands of dead Earths, they are able to never be chock-full, and nobody is concerned about the populace becoming two trillion in fifty years roughly.
Clarence finds he includes a problem. There are noises and rumbling disturbing the silence of his domain. Naturally, he does what persons usually do, and complains to the authorities. At the Housing Bureau are two co-workers; Bill Ching, who believes fervently in the parallel Earths as the answer, and Alec Mishnoff, who worries about something he only hints at to others. Both consent to visit Clarence’s Earth to look at the mysterious sounds. With a seismograph they determine that the rumbles are because of some sort of surface activity, not deep earthquakes. To have a location, someone must leave the force field and create a second seismograph.