A massive, 200-million-ton asteroid hurtles through space, carrying the explosive potential of every nuclear weapon on earth. As scientists track these celestial threats, they uncover evidence of past impacts that have reshaped our planet and altered the course of life itself. This documentary explores the terrifying reality of our cosmic neighborhood, where millions of space rocks orbit in a celestial shooting range, and investigates the cutting-edge science being developed to protect humanity from a potential extinction-level event.