Designed to facilitate the free exchange of ideas, the Internet has become home to confidential-even classified-information from virtually every nation in the world. Financial information, national infrastructure, even state secrets can be accessed via the complex computer network that is the World Wide Web. But how safe is that information if computer-literate teenagers can break into top-security computer systems, infect them with viruses, or steal sensitive-even dangerous-documents? FRONTLINE investigates the role of hackers and reveals how their exploits highlight the profound insecurities of the Internet and the software that drives it. Through interviews with teenagers, information warriors, security experts, and law enforcement officials, FRONTLINE illuminates a virtual world where many of our most sacred beliefs-including the very notion of bordered nations-are called into question.