In the futuristic setting of the Laboratory of Neuro Imaging at the University of California, Los Angeles, Alan gets a highly detailed scan of his brain - which for a man in his early 70s, is in remarkably good shape. This image, projected on a huge curved screen behind him, is the starting point for a search within his brain - as well as the brains of others - for the essential components of the Human Spark; a search informed by what the previous two programs have revealed about the attributes that make humans unique. One of those faculties is language. Through both functional brain scans and high-tech EEGs, we probe for the language centers within Alan's brain,including those employed to recognize mistakes in grammar - and discover the way language allows us to manipulate symbols in our minds. He also untangles the complex story of a gene called FOXP2, visiting researchers in England and Germany as well as the US who are using FOXP2 as an exciting new window into how language may have evolved. Other functional scans of Alan's brain reveal a fascinating link between two of humans' most characteristic abilities - language and the use of tools.