This is the story of an armored combat vessel that opened up an entirely new chapter in naval warfare. At a critical moment of the American Civil War in 1861, the Navy commissioned the USS Monitor to test a daring idea-that a mechanical fighting machine could inflict a crushing defeat on Confederate forces. Not long after its legendary confrontation with the ironclad Merrimack, the Monitor sank in stormy seas off Cape Hatteras. Almost a century and a half after these stirring events, NOVA's cameras follow the Navy's risky efforts to salvage the secrets of the Monitor as it lies rusting on the ocean bottom.