Planet Nghi-Ung-Liang is an evolutionary curiosity. The higher organisms living on it do not know the earthly division into two sexes, combining the characteristics of both in one body. Initially possessing both male and (suppressed) female characteristics, upon reaching maturity, individuals determine their identity in individual combat. The world is a real biological paradise... the work of earthly scientists is complicated by one thing: the crown of Ngi-ung-liang evolution, with all the fundamental physiological differences, is too similar to earthly man... The unique course of evolution gives rise to strong curiosity, external resemblance to homo sapiens of local intelligent people - and their beauty - disorientate, and the way of life and psychology cause shock and real phobia. Earthling Nikolai, an ethnographer, will have to try to unravel the secrets of this impossible world. His job is to observe, without interference, the life and psychology of “people” during the period of medieval feudalism. He must become almost “one of us,”  but ultimately devoid of empathy; to be in the center of events - while remaining on the sidelines.