As dozens of top surfers from across the world arrive in Nazaré to train and prepare for a major big-wave competition, Garret McNamara continues to struggle with his physical injuries and mental preparedness. He knows he is not ready to surf in the competition but seeing the other surfers makes him consider competing anyway. Garrett also has misgivings about the state of safety plans at the competition, and tries to convince the organizers to beef up their plans.

This episode is centered around how science, in particular the work of Clair Patterson (voiced in animated sequences by Richard Gere[33]) in the middle of the 20th century, has been able to determine the age of the Earth. Tyson first describes how the Earth was formed from the coalescence of matter some millions of years after the formation of the Sun, and while scientists can examine the formations in rock stratum to date some geological events, these can only trace back millions of years. Instead, scientists have used the debris from meteor impacts, such as the Meteor Crater in Arizona, knowing that the material from such meteors coming from the asteroid belt would have been made at the same time as the Earth. Patterson also examined the levels of lead in the common environment and in deeper parts of the oceans and Antarctic ice, showing that lead had only been brought to the surface in recent times. He would discover that the higher levels of lead were from the use of tetraethyllead in leaded gasoline resulting in government-mandated restrictions on the use of lead.

In the third programme of the series, Aleks gives the lowdown on how, for better and for worse, commerce has colonized the web - and reveals how web users are paying for what appear to be 'free' sites and services in hidden ways. Joined by some of the most influential business leaders of today's web, including Eric Schmidt (CEO of Google), Chad Hurley (CEO of YouTube), Bill Gates, Martha Lane Fox and Reed Hastings (CEO of Netflix), Aleks traces how business, with varying degrees of success, has attempted to make money on the web. She tells the inside story of the gold rush years of the dotcom bubble and reveals how retailers such as Amazon learned the lessons. She also charts how, out of the ashes, Google forged the business model that has come to dominate today's web, offering a plethora of highly attractive, overtly free web services, including search, maps and video, that are in fact funded through a sophisticated and highly lucrative advertising system which trades on what we users look for. Aleks explores how web advertising is evolving further to become more targeted and relevant to individual consumers. Recommendation engines, pioneered by retailers such as Amazon, are also breaking down the barriers between commerce and consumer by marketing future purchases to us based on our previous choices. On the surface, the web appears to have brought about a revolution in convenience. But, as companies start to build up databases on our online habits and preferences, Aleks questions what this may mean for our notions of privacy and personal space in the 21st century

Laurent Ballesta has yet again challenged himself to a new world record: spend 28 days at a depth of 100 meters to reveal the luxuriant and unknown depths of the Mediterranean.
Because people have been travelling there for thousands of years, this sea is be­lieved to be without secrets. And yet, far below its surface, lie vast unexplored territories, luxurious gardens worthy of the finest tro­pical coral reefs. These natural wonders are inaccessible to the traditional diver, in a twilight zone, between 60 and 120 m, where there’s less than 1% of sunlight. If diving at such depths is always a challenge, staying there is a fan­tasy, a utopia that becomes reality in 'The Deep Med'.

Beginning with the origins of the universe in the Big Bang, Sagan describes the formation of different types of galaxies and anomalies such as galactic collisions and quasars. The episodes moves further into ideas about the structure of the Universe, such as different dimensions (in the imaginary Flatland and four-dimensional hypercubes), an infinite vs. a finite universe, and the idea of an oscillating Universe (similar to that in Hindu cosmology). The search into other ideas such as dark matter and the multiverse is shown, using tools such as the Very Large Array in New Mexico. Cosmos Update shows new information about the odd, irregular surfaces of galaxies and the Milky Way perhaps being a barred spiral galaxy

The second episode of the series immerses the viewer in a fascinating journey through the history of life on our planet, focusing on the evolution and adaptation of life in the seas. It begins billions of years ago, when the Earth was an inhospitable place and life was impossible on the surface due to a hostile environment. The documentary highlights how, beneath the waves, life began to flourish, protected from storms and other elements of nature. It addresses the development of photosynthesis by plankton and how this led to a significant change in the Earth's atmosphere, allowing the emergence of animal life.
This visually stunning narrative chronicles the evolution of various forms of marine life, from the earliest complex life forms to the appearance of the first fish and cephalopods. The documentary shows how marine life has influenced terrestrial life, emphasizing the impact of the 'greening' of planet Earth.