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

Particle physicist Prof. Brian Cox asks, 'What time is it?' It's a simple question and it sounds like it has a simple answer. But do we really know what it is that we're asking? Brian visits the ancient Mayan pyramids in Mexico where the Maya built temples to time. He finds out that a day is never 24 hours and meets Earth's very own Director of Time. He journeys to the beginning of time, and goes beyond within the realms of string theory, and explores the very limit of time. He discovers that we not only travel through time at the speed of light, but the experience we feel as the passing of time could be an illusion.

The idea of intelligence is explored in the concepts of computers (using bits as their basic units of information), whales (in their songs and their disruptions by human activities), DNA, the human brain (the evolution of the brain stem, frontal lobes, neurons, cerebral hemispheres, and corpus callosum under the Triune Brain Model), and man-made structures for collective intelligence (cities, libraries, books, computers, and satellites). The episode ends with speculation on alien intelligence and the information conveyed on the Voyager Golden Record.

More than twenty-five years after the world wide web was created, it is now caught in the greatest controversy of its existence: surveillance. With many concerned that governments and corporations can monitor our every move, we wil meet the hackers and scientists whose technology is fighting back". It is a controversial technology, and some law enforcement officers believe it is leading to 'risk-free crime' on the 'dark web' - a place where almost anything can be bought, from guns and drugs to credit card details. Featuring interviews with the inventor of the world wide web, Sir Tim Berners-Lee, and the co-founder of WikiLeaks, Julian Assange, we delve inside the 'dark web'.

The journeys of the Voyager probes is put in the context of the Netherlands in the seventeenth century, with a centuries-long tradition of sailing ship explorers, and its contemporary thinkers (such as Constantijn Huygens and his son Christian). Their discoveries are compared to the Voyager probes' discoveries among the Jovian and Saturn systems. In Cosmos Update, image processing reconstructs Voyager’s worlds and Voyager’s last portrait of the Solar System as it leaves is shown.

Professor Richard Fortey delves into the fascinating and normally-hidden kingdom of fungi. From their spectacular birth, through their secretive underground life to their final explosive death, Richard reveals a remarkable world that few of us understand or even realise exists - yet all life on Earth depends on it. In a specially-built mushroom lab, with the help of mycologist Dr Patrick Hickey and some state-of-the-art technology, Richard brings to life the secret world of mushrooms as never seen before and reveals the spectacular abilities of fungi to break down waste and sustain new plant life, keeping our planet alive. Beyond the lab, Richard travels across Britain and beyond to show us the biggest, fastest and most deadly organisms on the planet - all of them fungi. He reveals their almost magical powers that have world-changing potential - opening up new frontiers in science, medicine and technology.