Sixty-five million years ago, a comet hit the earth, putting an end to life as it then was. Now a comet is about to hit the earth again. In the dramatised part of this episode, Fernando Martinez, a Mexican who works in Houston, Texas, sets off home to be with his family, the Vaton family in France seeks shelter, and the Baka pygmy tribesmen continue to hunt, unaware of the impending disaster. Astrophysicist Noah Boyle, and computer scientist Shiang Yatan, remain at the observation centre in Hawaii to try to find out exactly when the comet will hit.