The topic of stem cells has been a matter of great debate for our generation. No other subject straddles the line between life and death such as the question over the validity of the use of stem cells to improve the lives of those who seem beyond repair. Led by a pioneer in the science world, Stephen Hawking, this special takes us on a journey which delves into the subjects of stem cells both embryonic and adult to explore what these wondrous and baffling mechanisms are capable of, what exactly stem cells are and if they are the key to our future or a ticking time bomb waiting to detonate?