Brian Cox and Robin Ince transport the cage of infinite proportions to the Manchester Museum of Science and Industry. They are joined on stage by impressionist Jon Culshaw and astrophysicists Sarah Bridle and Tim O'Brien as they look up at the sky to discover that everything we see only accounts for 5% of the entire universe. So what is the rest of the universe made of? What are these mysterious elements known as Dark Matter and Dark Energy and would their discovery mean a complete re-writing of the laws of physics as we know them? Producer: Alexandra Feachem.