Michael Portillo resumes his exhilarating tour of San Francisco to find that diversity has been at the heart of the city since the days of the gold rush, though not always harmoniously so. Following his Appleton's guide, Michael heads to Chinatown to hear of the huge contribution Chinese immigrants made to the economy, working as miners and building the transcontinental railroad. He discovers an entrepreneurial community who overcame discrimination laid down by the law, and finds that fortune favours the brave with iconic Chinese treats created in America!

Intrigued by a reference in his guidebook, Michael goes in search of lavish public baths to unpack a landmark incident in 1897 whereby an African-American sued one of the richest white men in the state. At one of the oldest private athletics clubs in America, Michael gets to grips with the sport of handball, first brought to San Francisco by Irish immigrants in the 1850s. And joining the police's Marine Unit, he heads out into the bay with a force who has been keeping the waters safe since the 1860s.