The express purpose of the Company's planet-manufacturing business is to create dispersed branches of humanity, diverse enough to ensure the whole species' survival for eternity.

On occasion, however, mischievous Company employees attempt to place anomalous objects in the strata as practical jokes, like running shoes and other out-of-place artifacts, hoping to raise confusion among future archaeologists when the planets' beginnings have been long forgotten.

However the Company forbids this, and secretly monitors the generated strata in order to detect embedded jokes, fearing such actions may cause the collapse of entire civilizations when the artifacts are eventually unearthed.

Jago Jalo is a human who returned from a relativistic journey he embarked on more than a thousand years ago, where he made a stunning discovery: A flat Earth.

Kin Arad is shocked by the large store of weapons on-board Jalo's spaceship, and has misgivings about the expedition; Silver and Marco, however, see the possibility of reaping great technological rewards and launch the vessel on autopilot.

Also, Venus is conspicuously lacking its giant (lunar-sized) moon "Adonis", which dominates the sunset sky on the Earth Kin Arad came from, which was formative in leading humanity to an early heliocentric world view.

Since only the Eastern hemisphere of Earth is represented, the continent of America is completely missing, so Kin, Marco, and Silver rescue a party of Vikings in the process of searching for Vinland, when their ship is about to sail over the edge of the world.

She is excited about the massive task at hand; just like the parallel character Louis Wu in Ringworld, Kin is over two hundred years old, and in danger of becoming tired of life.

Before humans, there were the Great Spindle Kings, a race of acutely claustrophobic telepaths, who could live only a few hundred per planet and therefore built entire worlds from scratch to accommodate their population.