150 years ago, the first Welsh settlers arrived in Patagonia and many of their descendants still live in a small community in the south of Argentina. This documentary follows a group of archaeologists who believe they may have excavated bones belonging to the first Welsh woman to die there, in 1865. To solve the mystery once and for all, they locate Nia Olwen Ritchie, a fire fighter from present-day northern Wales, who travels to Argentina to donate her DNA.