Tyson begins the episode by explaining the nature of the speed of light and how much of what is seen of the observable universe is from light emanated from billions of years in the past. Tyson further explains how modern astronomy has used such analyzes via deep time to identify the Big Bang event and the age of the universe. Tyson proceeds to describe how the work of Isaac Newton, William Herschel, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time. Tyson describes the concept of dark stars as postulated by John Michell which are not visible but detectable by tracking other stars trapped within their gravity wells, an idea Herschel used to discover binary stars. Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1. Tyson uses the Ship of Imagination to provide a postulate of the warping of spacetime and time dilation as one enters the event horizon of the black hole, and the possibility that these may lead to other points within our universe or others, or even time travel. Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.

A Chapter of forgotten history. The first permanent European settlement in the United States was founded in 1565–two generations before the settlements in Jamestown and Plymouth–not by English Protestants, but by the Spanish and a melting pot of people they brought with them from Africa, Italy, Germany, Ireland and even converted Jews, who integrated almost immediately with the indigenous tribes.
The film uncovers one story of America’s past that never made it into textbooks. Follow some of America’s leading archaeologists, maritime scientists, and historians as they share the story of Florida’s earliest settlers. It’s a story that has taken more than 450 years to reveal.

Agnes Varda, one of the leading lights of France's honored French New Wave cinema era, and professional photographer and muralist, J.R., partake on a special art project. Together, they travel around France in a special box truck equipped as a portable photo booth and traveling printing facility as they take photographs of people around the country.
With that inspiration, they also create special colossal mural pictures of individuals, communities and places they want to honor and celebrate. Along the way, the old cinematic veteran and the young artistic idealist enjoy an odd friendship as they chat and explore their views on the world as only they can.

This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

Carl Sagan opens the program with a description of the cosmos and the Spaceship of the Imagination. The ship journeys through the universe's hundred billion galaxies, the Local Group, the Andromeda Galaxy, the Milky Way, the Orion Nebula, our Solar System, and finally the planet Earth. Eratosthenes' successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the Ages of Science are described, before pulling back to the full span of the Cosmic Calendar.

A heroic congressman, Leo Joseph Ryan Jr, travels to Jonestown; some Temple members plot their escape. Jim Jones realizes the walls are closing in and plans his final stand. After the massacre, the world learns about mass murder/suicide in Jonestown, orchestrated by cult leader. Survivors try to piece their lives back together.