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.

We move around in space, but we are stuck in a prison of time moving ever forwards. Einstein said, 'The distinction between past, present and future is only a stubbornly persistent illusion.' Is our experience of the ticking clock merely a trick of the mind? Could science ever make the clock move backwards? Experiments in quantum physics are showing that the future influences the present: what happens later limits the choices we think we have now. The laws of physics say visiting or talking to ourselves in the past is possible – but changing history once we get there is not.

In the last in the series Professor Jim Al-Khalili explores how studying the atom forced us to rethink the nature of reality itself. He discovers that there might be parallel universes in which different versions of us exist, finds out that empty space isn't empty at all, and investigates the differences in our perception of the world in the universe and the reality.

Einstein's world-shaking Theory of Relativity says that time travel is perfectly possible -- if you're going forward in time. Finding a way to travel backwards requires breaking the speed of light, which so far seems impossible. But now, strange-but-true phenomena such as quantum nonlocality (where particles instantly teleport across vast distances) may give us a way to make the dream of traveling back and forth through time a reality. Step into a time machine and rewrite history, bring loved ones back to life, control our destinies. But if succeed, what are the consequences of such freedom? Will we get trapped in a plethora of paradoxes and multiple universes that will destroy the fabric of the universe?

Comedian Ben Miller returns to his roots as a physicist to try to answer a deceptively simple question: what is one degree of temperature? His quest takes him to the frontiers of current science as he meets researchers working on the hottest and coldest temperatures in the universe, and to a lab where he experiences some of the strangest effects of quantum physics - a place where super-cooled liquids simply pass through solid glass. Plus, Ben installs his very own Met office weather station at home. Ben's investigations in this personal and passionate film highlight the importance of measurement and accuracy in the 21st century.

Humanity’s potential seems limitless. But could we become as powerful as God? Scientific breakthroughs grant our species seemingly divine abilities. Biologists tinkering with DNA are figuring out ways to grow new life forms, while neuroscientists try to create artificial consciousness. Statisticians around the world are using big data to predict the future and computer scientists have discovered a "God algorithm" that could solve any global problem in an instant. But to truly become God, we not only have to be all knowing, but all being. Quantum physicists are figuring out how to teleport matter at the speed of light!