The rock pocket mouse is a living example of Darwin's process of natural selection. Not only is evolution happening right now everywhere around us, but adaptive changes can occur in a population with remarkable speed. This speed is essential if you're a desert mouse living in an environment where a volcanic eruption can reverse selective pressure in nearly an instant. The film features Dr. Michael Nachman, whose work in the field and in the lab has quantified the selective pressure of predators and identified the genes involved in adaptation. In a complete story, from ecosystem to molecules, pocket mice show us how random changes in the genome can take many paths to the same adaptation—a colored coat that hides them from predators.