Mightiest of ocean liners, the Titanic lies two-and-a-half miles down in the North Atlantic And in her hold - perhaps the only amount anywhere of an incredibly rare substance that could make the free world invulnerable to foreign attack forever! The Americans want it So do the Russians And the sea never gives up its secrets without a struggle Which makes the task facing ace maritime troubleshooter Dirk Pitt one of the most stupendous tests of human courage and ingenuity ever