Time has increasingly become an obsession for the human race. Our internal body clocks dictate many of our actions despite the fact that we have introduced cryogenics and plastic surgery to cheat ageing and freeze life. The idea of controlling time - being a "timelord" - is an attractive one, but is it really possible that one day, perhaps by travelling at the speed of light, we might be able to walk with dinosaurs or go to visit our future descendants? Narrated by Jeremy Vine, the last part of this series examines this question and asks whether the humble worm holds the secret to eternal life.