Winding through Lisbon's cobbled streets, from its steep hills to the picturesque shoreline, the riches they encounter reveal the city's history. From a spectacular monument, to the maritime globetrotting of Portugal's 'golden age', and the work of a photographer documenting the city's African population, they discover a complex history of former glories and a darker, slave-trading past. Their journey also uncovers the impact of 20th-century dictatorship on the city's artistic and cultural life, through the work of artists Paula Rego and Joana Vasconcelos. They discover how the city's location on the west coast of Europe, looking out to the Atlantic, has shaped the city's cosmopolitan spirit - in one of the city's fado clubs, Alastair and Nina enjoy the popular Portuguese folk music whose melodies celebrate a yearning for home, once sung by sailors dreaming of their return.