The fourth episode sees host Neil deGrasse Tyson exploring our eternal quest to end hunger and honoring Nikolai Ivanovic Vavilov, pioneer of modern plant breeding, who risked his life for a discovery that would change the history of science. Vavilov's story is marked by both the tenacity and creativity and is particularly tragic. Interwoven into Vavilov's somber narrative are warnings and treatments of science and its ethical implications, especially when science itself comes under attack from political forces.

A child lies on the rug of a tenement dreaming of interstellar adventures. At the dawn of the space age, a young Carl Sagan’s career is forged in the clash of his mentors, two scientific titans. Sagan goes on realize his childhood dreams, to carry their research forward and communicate its significance to the whole world.

Episode 7 focuses specifically on first contact and the search for intelligent life in the vastness of the cosmos. Are humans ready to make first contact with other intelligent beings? Is our technology even sophisticated enough to detect communication signals from another world? Who are we to search for alien intelligence when we can't even recognize or respect the consciousness all around us, or even beneath our feet.
Neil deGrasse Tyson reveals the hidden underground network that is a collaboration of four kingdoms of life, and a true first contact story between humans and beings who communicate in a symbolic language and have maintained a representative democracy for many tens of millions of years.

The 8th episode reviews Giovanni Cassini's life. His observations of Saturn and its moons would have an enduring effect on the scientific world. Neil deGrasse Tyson also narrates the mysterious untold story of the scientist who figured out how to go the Moon while fighting for his life in a WWI trench. Aleksandr Shargei changed his name to Yuri Kondratyuk out of fear for his life and wrote a manuscript on rocket motion and space colonization. This letter would end up capturing the attention of an engineer working on the Apollo program, John Houbolt, and would made the Apollo Mission possible.
We will also know the saga of the twenty-year long odyssey of Cassini-Huygens spacecraft, a robotic explorer ordered to commit suicide on another world.

We inhabit a cosmos of undiscovered dimensions and paradoxical realities. We live on one level of perception, but there are others. Every once in a while, a searcher happens upon the doorway to one of these other levels. One of them discovered a paradox about reality that proved to be so profound, we have yet to understand how it could be possible. The universe, or perhaps we should say, universes have never been the same.
In the counterintuitive realm of quantum mechanics, light can be two contradictory things, and somehow - no one knows how - an unseen observer can alter the nature of reality. The man who stumbled on this hole in reality and the still- unfolding technological revolution that it made possible.

When Homo sapiens, which means 'wise ones,' discovered and controlled fire hundreds of thousands of years ago, everything changed. Fire allowed us to cook food and heat dwellings, and it served as a focal point for storytelling and sharing cultural identity among community members. We don't yet have established parameters for what it means to be 'distinctly human,' It would seem the only thing that separates us from other animals, Neil deGrasse Tyson ponders, is our neurotic need to feel 'special'. Against the backdrop of the Halls of Extinction, Tyson insists that there must be a clear distinction between ourselves and animals that justifies our eating them, wearing them and even bringing an end to their species.
From the birth of the devil in ancient Persia to a searing story of saintliness among macaque monkeys, this episode is an exploration of human potential for change. It concludes with the story of how one of history's greatest monsters was transformed into one of its shining lights.