Michael Mosley shows how existence is a struggle and how, minute by minute, from your first breath to your last, your body performs countless small miracles to keep you alive. He meets remarkable people who demonstrate how well the human body adapts to extreme environments: Herbert, world-champion free-diver, who can hold his breath in the depths of the ocean for up to nine minutes; Wim, the Ice Man, who can swim in glacial lakes so cold that would kill a normal person and Debbie who has lived for 10 years on a diet of crisps. And finally we see what happens when your body finally fails; we share the last moments of Gerald, an 84 year old, as he passes away at home with his family gathered around him. Contains mild sex references, scenes of surgery, childbirth and death.