HUMAN BODY DETECTIVES. BATTLE WITH THE BUGS In the Human Body Detectives (HBD) audio CD series, two young Human Body Detectives, Merrin and Pearl, magically enter different systems in the body to solve a health mystery. Through action packed fiction stories, listeners learn how the various systems work and what foods best fuel each system. In their second case, Merrin and Pearl's cousin is sick, threatening everyone's Mexican holiday. This time the girls find themselves in Max's body, witnessing firsthand the immune system in action. They befriend a white blood cell warrior who leads them into battle against the offending bacteria...