With his Edwardian Bradshaw's railway guide tucked under his arm, Michael Portillo begins the last leg of his journey from Hull to Caernarfon. In picturesque Snowdonia, he braves the fastest zip line in the world - stretching 1,500 feet across a vast slate quarry. He uncovers a bitter industrial dispute between quarrymen and the owner of the pit, Lord Penrhyn, which divided the community at the beginning of the 20th century.Riding north Wales's splendid heritage railways, Michael visits the home of British mountaineering, Pen y Gwryd, to hear how an Edwardian journalist and poet created a climbing community, which grew to include men who would conquer Everest in the 1950s. Michael meets the grandson of one of his political heroes, the Edwardian prime minister David Lloyd George, at his birthplace in Criccieth. At the impressive 13th-century fortress of Caernarfon, built by English King Edward I, Michael discovers the early 20th-century history behind the ceremony now traditional at the royal investiture of a Prince of Wales.