Long hailed as the grand master of adventure fiction, Clive Cussler has continued to astound with the intricate plotting and astonishing set pieces of his novels. Now, with a surprising twist, he gives us his most audacious work yet. .In the final pages of *Valhalla Rising*, Dirk Pitt discovered, to his shock, that he had two grown children he had never known-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 inf