Through a mix of crime-lab science, archeology, and history, this NOVA/National Geographic special presents new evidence that is changing what we know about the final days of the once-mighty Inca Empire. This probing story of archeological discovery begins in a cemetery crammed with skeletons that offer tantalizing clues about a fierce 16th-century battle between warriors of the collapsing Inca Empire and Spanish invaders. Now, the long-accepted account of a swift Spanish conquest of the Inca—achieved with guns, steel, and horses—is being replaced by a more complete story based on surprising new evidence, including what may be the first gunshot wound in the Americas.