The second deadly hour examines more threats–both natural and manmade–that may endanger civilization. From the far reaches of space to tiny viruses, doomsday sources are many. But so are technologies used to keep doomsday at bay. Asteroids of significant size have hit our planet before and likely will again. Asteroid hunters demonstrate the Near Earth Asteroid Tracking (NEAT) program and methods being developed to destroy earth-aimed asteroids. Then, it's onto bioterrorism's sinister technologies–how highly virulent agents like smallpox and plague can be weaponized. Next, an ex-hacker turned cyber-security expert shows how vulnerable the nation's computers are to cyberterror. Finally, we visit the controversial world of biotechnology. Could genetically engineered crops backfire? Does a brave new world of genetically selected beings loom in our not-so-distant future?