En 1942, un sous-marin allemand torpille le «Laconia», un navire transportant des troupes anglaises. Werner Hartenstein, commandant du submersible, donne l'assaut pour capturer les officiers à bord du bateau britannique. Il découvre alors la présence de civils, parmi lesquels des femmes et des enfants...

In 2099, Earth has shifted off its axis and begins to rotate at an angle of 90% to the 20th-century equator. Three years of natural disasters follows, and when things settle down, Earth's ten billion population has died and only two million moon colonists remain.

Some return to begin the repopulation of the world in seven new cities and the remaining colonists of the moon fear that their former neighbors might pose a threat and construct a ring of defensive satellites to trap them on the newly repopulated homeworld.