To appease the goals, Thorinn's step-father seals him in a deep well, with the geas (over-powering mental command) to "go down". So Thorinn does for the rest of the book which takes him level by level deeper into a far future earth. A fantasy-style journey, but mostly SF, except for the unexplained mechanism of the geas. Snippets at the beginning of some chapters fill in some of the background of how things came to be, and there's some fairly restrained info-dumps at the end. Thorinn is ignorant but clever. A talking box picked up early in the journey helps serves as a miniature deus ex machina at various points. The problem is that there's nothing much to care about. Other than surviving, nothing is at stake. Places visited are never seen again.

Not bad but nothing to recommend seeking it out either. ( )