The Romanov ransom / Clive Cussler and Robin Burcell.

In 1918, a ransom of enormous size was paid to free the Romanovs from the Bolsheviks, but, as history knows, the Romanovs died anyway. And the ransom? During World War II, the Nazis stole it from the Russians, and after that--it vanished. Until now. When a modern-day kidnapping captures the attention of husband-and-wife team Sam and Remi Fargo, the couple soon learn that these long-lost riches may be back in play, held in trust by the descendants of a Nazi guerrilla faction called the Werewolves. It is their mission to establish the Fourth Reich, and their time is coming soon. As the Fargos follow the trail across Europe, Northern Africa, and South America, they know only one thing. This quest is greater than anything they have ever done--it is their chance to make someone answer for unspeakable crimes, and to prevent them from happening again