"At the end of Valhalla Rising, Dirk Pitt discovered, to his shock, that he had two grown children he had never known about, twenty-three-year-old fraternal twins born to a woman he thought had died in an underwater earthquake. Both have inherited his love of the sea: the girl, Summer, is a marine biologist; the boy, himself named Dirk, is a marine engineer. And now they are about to help their father in the adventure of a lifetime. There is a brown tide infesting the ocean off the shore of Nicaragua. The twins are working in a NUMA underwater enclosure, trying to determine its origin, when two startling things happen: Summer discovers an artifact, something strange and beautiful and ancient; and the worst storm in years boils up out of the sky, heading straight for them--and for a luxurious floating resort hotel square in its path. The peril for everybody concerned is incalculable, and, desperately, Pitt, Al Giordino, and the rest of the NUMA crew rush to the rescue, but what they find in the storm's wake makes the furies of nature pale in comparison"--Container.