Clive Cussler?s The Corsican Shadow

France, May 1940. As the German army blitzes Europe, a curator must take a mysterious cargo out of the country. When his intended ship sinks, his cargo's uncertain fate rests on a decrepit steamer, sailing under German fire. Decades later, a diving expedition leads Dirk Pitt to a shipwreck's cache of uncut diamonds. No sooner than discovered, the diamonds are stolen - all while vital water treatment facilities around the globe are being targeted, placing humanity in grave peril. Only Dirk Pitt can locate the treasure that will preserve the soul of a nation... and save the world from catastrophe.