Andy McGrath explores Roman Wales, visiting ancient sites and tracing Welsh Druidry's final stand on the Isle of Anglesey. He discovers a hidden museum and hears a tale from folklorist Maxine Allinson about St. David's miraculous birth. In Carmarthen, he connects with Merlin's Oak and learns about local physicians. His journey ends in Snowdonia, where he investigates the battle behind the mountain's name.

Andy McGrath embarks on an inspiring journey back to Somerset, where he conducts a ghost hunt in the infamous Shepton Mallet Prison, and visits the magnificent SS Great Britain in Bristol.