In the caves and rock shelters of the Dordogne region of France, Alan Alda witnesses spectacular paintings and carvings that date back 30,000 years.

We are separated from our nearest relatives, the chimpanzees, by only one or two percent of our genes, but also by some six million years of going our different evolutionary ways. Alan Alda sets out to explore that difference, and quickly finds that the scientists studying chimps are themselves separated into opposing worldviews.

In the futuristic setting of the Laboratory of Neuro Imaging at UCLA, Alan gets a highly detailed scan of his brain. This image is the starting point for a search for the essential components of the Human Spark.