Out of Control: It's estimated that one out of four people suffer from some form of allergy but few reactions are as severe as Phoebe's, a young woman who has been stung by a jellyfish. As her immune system launches a full-scale assault on the toxins, travel through her bloodstream to examine the plan of attack. Take a provocative look at the varied and complex processes that go on inside all of us from the way our natural defense systems treat injuries to the everyday functions our bodies carry out. Spreading Menace: While eating at a friend's birthday party, Mike ingests Salmonella bacteria and falls ill. Follow the trail of the invading microbes through the digestive system from the mouth to the lower intestine and examine the body's formidable arsenal of weapons designed to combat these tiny terrors. Teen Dreams: Follow the flow of hormones from pituitary glands on through the bloodstream of two young teens, Darren and Natalie, as the dramatic effects of puberty unfold. The month culminates with Natalie's first menstruation and a weekend party during which Darren's body seemingly does everything it can to ruin his chances with Natalie.