The inhabitants of post-apocalypse Labrador have vague knowledge of the "Old People", a technologically advanced civilization they believe was destroyed when God sent "Tribulation" to the world to punish their forebears' sins. The inhabitants practise a form of fundamentalist Christianity; they believe that to follow God's word and prevent another Tribulation, they must preserve absolute normality among the surviving humans, plants and animals, and therefore practice eugenics. Humans with even minor mutations are considered blasphemies and either killed or sterilized and banished to the Fringes, a lawless and untamed area rife with animal and plant mutations, and suggested to be contaminated with radiation. Arguments occur over the keeping of a tailless cat or the possession of over-sized horses. These are deemed by the government to be legitimate breeds, either existing before or achieved through conventional breeding. The government's position is considered both cynical and heretical by many of the orthodox frontier community, and it is suggested that they support the usage of these animals for the sole purpose of their greater efficiency.
The inland rural settlement of Waknuk is a frontier farming community, populated with hardy and pious individuals, and is where the story mainly takes place. David Strorm, the son of Waknuk's most religious man, Joseph Strorm, has dreams of large cities and "horseless carts", although he does not understand why he has these dreams or what they mean, and is cautious about mentioning it to his father, lest he raise suspicion that he's a mutant. He makes friends with Sophie, a girl who secretly has six toes on one of her feet. Later, Sophie's family attempts to escape from the reprisals (ceremonies in which blasphemies are sterilized) when her wet footprints are seen and reported by a local boy.
David and a few other children in Waknuk hide their own form of mutation, telepathy. David's Uncle Axel, who learned about the group from talking to David about his telepathy when he was young, advises David and protects them from persecution. He commends David on the wisdom of hiding his and the others' ability, and later kills the husband of one of the group's members who was planning to blackmail the telepaths. David's younger sister Petra demonstrates exceptionally strong telepathic talent when her horse is attacked by a wildcat—she calls to all the telepaths for help across the entire Waknuk area, and stuns those closest to her. That leads to suspicion from the locals, and Uncle Axel warns the group, via David, that the Inspectors are beginning to investigate them.
Later, two telepaths, Katherine and Sally, are captured and tortured for information, while David, his cousin Rosalind and Petra escape to the Fringes. A group of men from various districts band together to track and capture the telepaths—unknown to the Norms, the posse includes a telepath named Michael who keeps the escaping group informed of the trackers' progress. Later, with Petra's strong telepathic abilities, they contact a society with telepaths in a different country they mistakenly refer to as "Sealand" (New Zealand). With the help of Sophie, who is now living in the Fringes, they escape the hunters and are rescued by a Sealand expedition. Unfortunately, they do not have enough fuel to take the craft back to Waknuk to pick up Rachel, the lone remaining Waknuk telepath, so they continue to Sealand. Michael vows to return to Waknuk to rescue Rachel, and join them in Sealand however they can.
