After the misadventures of the first two books Lenk and his companions must finally turn away from fighting each other and for their own survival and look to saving the entire human race. A terrible demon has risen from beneath the sea and where it came from thousands could follow. And all the while an alien race is planning the extinction of humanity. The third volume in the Aeon's Gate trilogy widens the action out dramatically. TOME OF THE UNDERGATES was based mainly on a ship, BLACK HALO moved the action to an island of bones, THE SKYBOUND SEA takes us out into a world threatened with a uniquely imagined and terrifying apocalypse.