Stress has been called the epidemic of this century. For our prehistoric ancestors, the body's natural response to stress ensured human survival. Today, scientists believe the chronic stresses of modern life may be turning our bodies' natural protection against us. Why do aggressive people suffer more heart attacks? Why do children raised in high stress environments reach puberty at an earlier age? From a crowded inner-city school to a serene ocean-side community, The Nature of Things explores stress in the modern age.