Is there any way to slow or even prevent the ravages of time? Veteran presenter Johnny Ball looks back over the 45 years that Horizon - and he - have been on air to find out what science has learned about how and why we grow old. Charting developments from macabre early claims of rejuvenation to the latest cutting-edge breakthroughs, Johnny discovers the sense of a personal mission that drives many scientists and asks whether we are really any closer to achieving the dream of immortality.