The Universe as we know it is condemned to death. Space, matter and even time will one day cease to exist and there's nothing we can do about it. Harsh realities are revealed about the future of our Universe; it may collapse and burn or it might be gripped by a galactic ice age. Either of these scenarios might be a long way off. However, our Universe could suddenly be destroyed by a "random quantum fluctuation", a bubble of destruction that can obliterate the entire cosmos in the blink of an eye. No matter how it ends, life in our Universe is doomed.

Is mankind alone, or are there aliens out there, either waiting to be discovered, or on their way to find Earth? Professor Brian Cox spends this episode asking such questions, and what he discovers may raise a few eyebrows. He begins by exploring the human race's efforts to find neighbours in outer space, including the launch of two golden discs containing a greeting from Earth in the 1970s; they are still travelling and are now the most distant man-made objects from the planet. Brian also meets members of the Search for Extra-Terrestrial Intelligence, who have been monitoring radio signals for 50 years without success, before discussing the ingredients needed to make an intelligent civilisation with astrophysicist Dr Frank Drake.

Academy Award-winning director Alex Gibney (Taxi to the Dark Side) masterfully explores the fall of the disgraced cycling champion following the 2009 Tour de France, making use of his extraordinary access to attain rare interviews with former teammates, alleged doping mastermind Dr. Michele Ferrari, and Armstrong himself. What was Lance Armstrong thinking? For years, after seizing international fame as the cancer survivor who won seven Tour de France titles, he fiercely denied accusations that he used performance-enhancing drugs. He used his power to aggressively litigate journalists and publicly humiliate former friends who claimed otherwise. His deceit finally cracked in January 2013, when he admitted guilt to Oprah Winfrey in a television interview that critics decried for only scratching the surface. Academy Award-winning director Alex Gibney approaches Armstrong with unique and extraordinary access. In 2009, Gibney was commissioned to make a film about Armstrong's return to the Tour de France, four years after the racing champion had declared retirement. That race would later stir up devastating evidence in the case against Armstrong. But Gibney came away from the experience unable to reconcile the discrepancy between doping allegations and Armstrong's emphatic denials. Then, post-Oprah, Gibney went back to Armstrong for new interviews to extract a more detailed account of his double life. In The Armstrong Lie, Gibney masterfully explores the complexities of the case, interweaving the dramatic action of the 2009 Tour de France, when Armstrong found himself unexpectedly competing against his own teammate Alberto Contador. Gibney attains rare interviews with Armstrong's former teammates and alleged doping mastermind Dr. Michele Ferrari. The film also raises troubling questions about the process of doping regulation. Recently, when asked to give advice to documentary filmmakers, Gibney responded with a motto exemplified by this film: "Embrace contradictions."

Prepare yourself for an unparalleled sensory experience. Samsara reunites director Ron Fricke and producer Mark Magidson, whose award-winning films Baraka and Chronos were acclaimed for combining visual and musical artistry. Samsara explores the wonders of our world from the mundane to the miraculous, looking into the unfathomable reaches of humanity's spirituality and the human experience. Neither a traditional documentary nor a travelogue, Samsara takes the form of a nonverbal, guided meditation.

Fourth episode examines how plants either share environments harmoniously or compete for dominance within them. Attenborough highlights the 1987 hurricane and the devastation it caused. However, for some species, it was that opportunity for which they had lain dormant for many years. The space left by uprooted trees is soon filled by others who move relatively swiftly towards the light. The oak is one of the strongest and longest-lived, and other, lesser plants nearby must wait until the spring to flourish before the light above is extinguished by leaves. Tropical forests are green throughout the year, so brute force is needed for a successful climb to the top of the canopy: the rattan is an example that has the longest stem of any plant. As its name suggests, the strangler fig 'throttles' its host by growing around it and cutting off essential water and light. Some can take advantage of a fallen tree by setting down roots on the now horizontal trunk and getting nutriment from the surrounding moss and the fungi on the dead bark. The mountain ash (eucalyptus regnans) grows so tall, that regeneration becomes a considerable problem. It is easily flammable, so its solution is to shed its seeds during a forest fire and sacrifice itself. It therefore relies on the periodic near-destruction of its surroundings in order to survive. Attenborough observes that catastrophes such as fire and drought, while initially detrimental to wildlife, eventually allow for deserted habitats to be reborn.

Zeitgeist Addendum attempts to locate the root causes of this pervasive social corruption, while offering a solution. This solution is not based on politics, morality, laws, or any other 'establishment' notions of human affairs, but rather on a modern, non-superstitious based understanding of what we are and how we align with nature, to which we are a part. The work advocates a new social system which is updated to present day knowledge, highly influenced by the life long work of Jacque Fresco and The Venus Project.