As we reach our 40s, our bodies are starting to show the effects of time. It is now that we face the results of the lifestyle we have led. And imperfections in our bodies, that we may have carried for years without knowing, may reveal themselves. This episode explores the body's ability to draw on its own reserves when things start to go wrong. It follows a man with a life-threatening aneurysm in the main blood vessel supplying his vital organs, a heavy smoker who has a build of carbon dioxide in her blood which is poisoning her brain, and a patient with a weak heart having a pacemaker implanted by robotic surgery.