On the morning of February 15, 2013, a 7,000-ton asteroid crashed into the Earth's atmosphere, exploded and fell to earth across a wide swath near the Ural Mountains. The Siberian meteor was captured by digital dashboard cameras, a common fixture in Russian cars and trucks. Within days, armed with this crowd-sourced material, NOVA crews, along with impact scientists, hit the ground in Russia to hunt for debris from the explosion and clues to the meteor's origin and makeup. Is our solar system a deadly celestial shooting gallery -- with Earth in the cross-hairs? What are the chances that another, even more massive, asteroid is heading straight for us? Are we just years, months or days away from a total global reboot of civilization, or worse?