This book begins with the discovery by the human race
of a vast underground system of caverns that extends worldwide
several miles deep and contains a civilization of humanoids
known as hadals. Setting aside plausibility problems for
the moment, the story is an interesting one, in the spirit
of most good science fiction. Not only does Long follow along
a few subplots (including, mainly, a team of scientists and
soldiers on a quest deep inside), but he also presents the
big picture occasionally and talks about some of the changes
this discovery brings about socially and politically.
The best plot was the main one. A subplot involving a
secret group of scholars trying to discover the nature of
Satan is not nearly as good as it could be. Overall, the
two main characters, Ali and Ike, are both well done. A major
antagonist, Isaac, is not given enough space to develop. What
little we see of him is gripping. Certainly a new author to
watch once this comes out in paperback.