When Ruby's poor eating habits result in an in-class fainting spell, Nurse Cutlip takes it upon herself to lecture the kids on the importance of proper nutrition, exercise and rest for the promotion of health. But down in the boiler room, Earl scoffs at the notion. Eat healthy? Exercise? Ha! He eats terribly, he doesn't exercise, and he's in fine physical form. But when Nurse Cutlip holds up an old photo of Earl as a warning of what could happen if they don't take care of their bodies, Earl becomes enraged. He morphs the school into his body, determined to give the kids an up-close and personal look at just how healthy he is. Our heroes are ambushed by a gang of bacteria, unpleasant thugs who have laid claim to this turf (Earl's body), and who challenge our heroes to a rumble. Marcus realizes that they are no match for the bacteria, but they know who is: the body's defenders, the white blood cells. Unfortunately, the white blood cells are a weak, sickly lot, lacking in self-confidenc