Derek Brockway kicks off the series in Gwynedd with a stunning ten-mile walk that starts and ends in Penryndeudreath near Porthmadog. His route follows part of the Ffestiniog railway line with a stopping point at Tan-y-Bwlch station. He learns about the industrialist who changed the landscape and takes shelter from the rain in a farmhouse kitchen, before exploring a Celtic rainforest. Meanwhile, Dr Jeni Millard visits a slate quarry now used to mature cheese, and Onkar Singh Purewal discovers the story of gardener John Ystumllyn, the first recorded black person in north Wales.