Some years ago a stash of family records was handed down to Michael Palin, among which were photos of an enigmatic young man in army uniform. This, Michael learned, was his Great-Uncle Harry, born in 1884, died in 1916. The quest that followed involved hundreds of hours of painstaking detective work. Michael tracked down what remained of his great-uncle Harry's diaries and letters. He walked the route Harry took on that fatal, final day of his life amid the mud of northern France. And as he did so, a life that had previously existed in the shadows was revealed to him.