Stone opens the episode on Vietnam with a review of American intervention in Latin America. Lyndon Johnson, according to Stone, disregarded JFK’s “memo” about withdrawing troops and instead escalated. The Cataclysm in Vietnam as the war reaches a turning point - there's no going back. The betrayal by Richard Nixon.

Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. It moves to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers and its implications for Earth's greenhouse effect. The Cosmos Update highlights the connection to global warming.

Caesar contemplates Pompey's counteroffer but Mark Anthony wishes the war. Vorenus continues to struggle as a businessman and must reevaluate his career choice. Atia schemes to come between Caesar and Servilia and Pullo seeks Octavian's help.

Guernica (1937) was created during Picasso's Surrealist period and captures the horror of the bombing of the Basque town of Guernica during the Spanish Civil War. By the end of World War II, Picasso had become an internationally known artist and celebrity.

Andrew Marr tells the story of the first empires which laid the foundations for the modern world. From the Assyrians to Alexander the Great, conquerors rampaged across the Middle East and vicious wars were fought all the way from China to the Mediterranean. But this time of chaos and destruction also brought enormous progress and inspired human development. In the Middle East, the Phoenicians invented the alphabet, and one of the most powerful ideas in world history emerged: the belief in just one God. In India, the Buddha offered a radical alternative to empire building - a way of living that had no place for violence or hierarchy and was open to everyone. Great thinkers from Socrates to Confucius proposed new ideas about how to rule more wisely and live in a better society. And in Greece, democracy was born - the greatest political experiment of all. But within just a few years, its future would be under threat from invasion by an empire in the east...

The simple act of making an apple pie is extrapolated into the atoms and subatomic particles (electrons, protons, and neutrons) necessary. Many of the ingredients necessary are formed of chemical elements formed in the life and deaths of stars (such as our own Sun), resulting in massive red giants and supernovae or collapsing into white dwarfs, neutron stars, pulsars, and even black holes. These produce all sorts of phenomena, such as radioactivity, cosmic rays, and even the curving of spacetime by gravity. Cosmos Update mentions the supernova SN 1987A and neutrino astronomy.