A group of explorers sets out on an expedition to find a legendary haven of knowledge and ancient wisdom, and in the process learn more about the people they only remember as "the Roadmakers".

In a post-apocalypse North America where almost everyone was killed by a plague over 1,700 years prior, little is known about the ancient "Roadmaker" civilization that is said to have built the devastated ruins of enormous cities, and the magnificent roads that still cover the landscape.

But along with trade comes the threat of new civilizations When a copy of Mark Twain's novel A Connecticut Yankee in King Arthur's Court is discovered in the estate of the sole survivor of an earlier expedition to the north, a young woman named Chaka Milana, whose brother died in the previous expedition almost a decade ago, decides to gather a band of explorers and try to find Haven, a legendary stronghold where the knowledge of mankind is said to have been collected and kept safe for future generations.

In their excitement at having finally reached their destination, Chaka and her group open the door that had sealed away the knowledge of the old world, spared from the destruction of the plague by the October Patrol, only to realize that they had made a mistake similar to the first expedition.

[2] One of the core themes of the book is the loss of knowledge and collective memory after an apocalyptic disaster: Even though the people of the Mississippi valley are aware of the remnants of the "Roadmaker" civilization, they have great difficulties understanding the purpose of certain concepts.