Starting the study of the basic elements of germ theory with bacteria; the anatomy and function of a bacterium cell; how bacteria can cause disease; how they can make themselves elusive to the immune system; three diseases caused by bacteria.

Examining the virus, which can replicate inside living cells; the life cycle of a virus; seeing what viruses like HIV and Ebola do to host cells; meeting the spirochete and rickettsia, two germs that fall between bacteria and viruses.

Fungal diseases can indirectly affect humans; they play a major role in human history; investigating infections that can be acquired when one comes into contact with mold or fungus; learning if a household duct system should be cleaned regularly.

The scientists that strengthen the foundations of modern medicine; meeting some of the people who develop the tools to identify microorganisms; the means to pinpoint the source of a disease; the vaccinations to prevent them; the drugs to treat them.

The history of antibiotic development; how the eight classes of antibiotics attack bacterial infections; an introduction to the concern of antibiotic resistance; learning how one can contribute to the more prudent use of antibiotics.