This program explores the complex and remarkable immune system and its vital role in the defense of our bodies.

It introduces students to the microorganisms and minute foreign particles surrounding us at all times, including the infectious viruses and bacteria that threaten us when these foes break through the body's outer defenses. It explores the nature of immunity, graphically presents phagocytes, T-cells, and B-cells, the defending heroes of the immune system, and outlines the phases of immune response — from recognition of the invader to the eventual slowdown of the battle as the invader is defeated.