This astonishing novel begins in 1907, when Josef Siedler, a science-fiction devotee, ventures deep into a series of caves in search of an entrance to the underworld. Disappointed in his quest, he nonetheless returns with a peculiar souvenir: a small rock sample that emits a strange humming sound. Upon Siedler's death, the rock is bequeathed to his nephew, a significant step in what will become an extraordinary journey through the arc of history...