In mid Wales, Kate and Teg get a taste of Stone Age life, mucking in with a farmer and an archaeologist who are building a medieval settlement to bring to life the past in order to understand how we used to live, and perhaps serve as a way to move forward. Next, they explore the potential death traps of our historical legacies at an old lead mine, where the South and Mid Wales Cave Rescue Team practice their skills using Teg as the damsel in distress. Kate learns about the plight of Welsh mountain ponies, whose numbers have dropped from the thousands to just a few hundred, by meeting one of the last breeders in Wales, whose family have been doing it since the 1800s. Finally, Kate discovers her legs are built for walking when she tries mountain biking in the Brecon Beacons National Park, powering her way up 2,358 feet towards the top of Fan-Y-Big.