At the beginning of this cosmic journey across space and time, Dr. Carl Sagan takes us to the edge of the universe aboard a spaceship of the imagination. Through beautiful special effects, we witness quasars, exploding galaxies, star clusters, supernovas, and pulsars. Returning to our solar system, we enter a re-creation of the Alexandrian Library, the seat of learning on Earth 2,000 years ago.

This episode is a historical re-creation of the life of Johannes Kepler, the last scientific astrologer, the first modern astronomer and the author of the first science fiction novel. Kepler provided insight into how the moon and the planets move in their orbits and, ultimately, how to journey to them. It's also a story about the scientific process of discovery, and how the search for truth is never easy but always worthwhile.