A massive, silent threat drifts through the cosmos, a colossal rock that holds the power to extinguish all life on earth in a single, catastrophic moment. As scientists race to understand the origins of these celestial wanderers, they uncover a history of violent impacts that have shaped our planet's past and could dictate its future. This is a gripping exploration of the cosmic forces that could bring about the end of humanity, and the desperate, high-stakes efforts to detect and deflect these potential planet-killers before they strike.