七都市物語 ～北極海戦線～

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.

In 2086, Earth's axis tilted 90 degrees and after three years span, approximately ten billion people died. One million colonists who had moved to the moon prior to the disaster escaped what later became known as "The Great Fall". At the moon, they established the Panhuman World Government and organized the recolonization of the world. Seven locations were chosen for cities as starting points for this massive project.