Picked up where the first book left off, and leaves things for a final book. That said, this is a solid middle-of-the-trilogy entry, better than the first book. We learn about the aliens, and Will learns more about himself. Finished this on the plane, then started (and finished) the third and final book.

The aliens Christopher has created are well detailed. While the initial idea of a tripod came from HG Wells, the physiology is developed (and believable) by this author. We get a glimpse of their world also, from heavier gravity to greenish (toxic) atmosphere. And the hint that this is all coming soon to a conquered planet near you!