The violent mega-eruption of Krakatoa in AD 535 threw enough volcanic matter into the earth's atmosphere to blot out a huge portion of the sun's rays, and this was the start of several years of almost ice-age-like conditions. Written records and other tangible evidence exists from China to the Americas of the tragic effects this event had on humans everywhere. Crops failed, famine came to pass, stillbirths increased, disease became rampant, trade slowed, and internecine wars were waged for food and also out of a paranoid sense of horror. Most of all humans became reactionary and turned to their gods for answers and for comfort. From Byzantium to India, Saxon England to Coptic Ethiopia, xenophobia reigned, foreigners were persecuted as possible offenders of the gods, and order disintegrated on a frighteningly vast scale. Life across the globe was disrupted as by the tens of millions people wondered if they were truly witnessing the end of the world.

This is the scene of Yarbro's seventeenth Saint-Germain novel. In the pages of Dark of the Sun, the perpetually-exiled Carpathian nobleman goes from a prosperous life as a merchant in Liang-era China to the life-threatening undertaking of traversing the Silk Road, a journey of three-years' duration, in order to return to the west. With Saint-Germain, as always, is his faithful companion Rogers, and along the path of the dauntingly perilous expedition west, Germain witnesses a world gone mad in the wake of unimaginable cataclysm.

Chelsea Quinn Yarbro revives a global catastrophe we had somehow forgotten, and uses it as a backdrop for a slow but detailed novel that takes her readers on a trip across nearly the whole of east and central Asia, from China to the Carpathians, sparing no detail or sociological observation along the way.