With the theory of Black Dwarf Stars, Professor Brian Cox considers the death of the universe, a time so far in the future it defies comprehension. Brian discovers that time is not characterised by repetition but by irreversible change. From the relentless march of desert sands to the erosion of a beached freighter, the ravaging effects of time are all around us. The vast universe is subject to these same laws of change. As we look out to the cosmos, we can see the story of its evolution unfold, from the death of the first stars to the birth of the youngest.