This book is the story of a secret expedition beneath the earth’s surface, down through geologic space and time to an imagined subterranean world. Narrated by Harry, one of the three adventurers, it tells how he, Professor Von Hardwigg and their guide, Hans Bjelke, descend the chimney of an extinct volcano eruption. The novel begins in the spring of 1863. Von accidently discovers a mysterious manuscript written by Arne Saknussemm, a sixteenth century Icelandic heretical philosopher and alchemist. They encounter many adventures, including prehistoric animals and natural hazards, before eventually coming to the surface again in southern Italy, at
the Stromboli volcano.