"Ancient Pern" is the fourth book in the series "The Horsemen of Pern" and follows the novels "Flight of the Dragon", "Wanderings of the Dragon" and "White Dragon". The book contains two novels that make up a dilogy about the ancient times of Pern, about a thousand years from the era of F'lar and Lessa, described in the first three works. The Sixth Passing of the Scarlet Star ends; the torrent of destructive Threads that have tormented Pern for decades is becoming less frequent; riders and dragons, residents of holdings and workshops are anticipating the onset of peaceful times And at this point, a new disaster falls on Pern a terrible epidemic brought to the inhabited zone of the planet by a mysterious animal from the southern mainland. The riders, along with the Harpmen's and Healers' Workshops, strain their last powers in search of an antidote; they travel through time and space looking for the magical elixir. In these harsh days, the names of two women, Morita and Nerilka, became known to many; women whose dedication saved the lives of hundreds of people.