Alcohol, smoking, and stress—in the body subjected to these irritants, the cells responsible for maintaining life seem to fight a war that never ends. Due to a severe shortage of workers, Red Blood Cell AA2153 has to quickly learn to deliver oxygen and collect carbon dioxide, even in dangerous conditions. Meanwhile, White Blood Cell U-1196 has to do her part by dealing with germs and viruses during life-threatening situations. In the midst of these crises, they have to work together to keep the body healthy, despite not knowing if their sacrifices will be worthwhile.