When Will Burrows and his friend Chester embark on a quest to find Will's archaeologist father, who has inexplicably disappeared, they are led to a labyrinthine world underneath London, full of sinister inhabitants with evil intentions toward "Topsoilers" like Will and his father.

As fourteen-year-old archaeologist Will and his friends plummet down a subterranean pore, they face deadly creatures and discover a strange fungal shelf, which not only reveals artifacts from ancient civilizations, but clues to a lost land at the end of the Earth.