What's really going on inside your stomach? In this documentary, Michael Mosley offers up his own guts to find out. Spending the day as an exhibit at the Science Museum in London, he swallows a tiny camera and uses the latest in imaging technology to get a unique view of his innards digesting his food. He discovers pools of concentrated acid and metres of writhing tubing which is home to its own ecosystem. Michael lays bare the mysteries of the digestive system - and reveals a complexity and intelligence in the human gut that science is only just beginning to uncover.