Hitler's Secret Attack on America: December 11, 1941: Hitler declares war against America. For German Admiral Karl Donitz, Commander of the U-boat submarine fleet, the time is at hand. Donitz devises a plan for a surprise attack on the U.S. Atlantic Seaboard, called "Operation Drumbeat". The message to the United States is clear; Hitler is coming... This story, one of the most deadly attacks off America's East Coast, is covered up and remains largely untold and secreted away for over 60 years --until now. For the first time, the story of these U-boats and their prey is being hunted down, uncovered and filmed by NOAA National Marine Sanctuaries. Using advanced Hi-Def ROV's, side scan sonar, and 3D imaging, this show will piece together the tactics, battles, heroes & villains of, "Operation Drumbeat", one of the most unknown and deadliest attacks on the U.S in history.