Things have been peaceful for Red Blood Cell when suddenly an abrasion occurs before her eyes. The White Blood Cells (Neutrophils) arrive to battle the bacteria and viruses invading through the wound, but they struggle against enemies like Staphylococcus aureus. Will the White Blood Cells (Neutrophils) find a way to defend this body?

Naive T Cell is patrolling the body for influenza virus proliferation. But since he’s never taken on the enemy before, he’s completely terrified and useless. He finally ends up fleeing the battlefield where White Blood Cell (Neutrophil) and the veteran Killer T Cells are fighting. Naive T Cell is filled with self-loathing until Dendritic Cell sees him and speaks to him kindly.

Let me become a great red blood cell one day... This is the story of Red Blood Cell before she became Red Blood Cell, when she was a young Erythroblast. The Erythroblasts are training hard to become full-fledged Red Blood Cells under the supervision of their teacher, Macrophage. But Erythroblast is directionally-challenged, and she’s always getting lost in the middle of drills. One day, while practicing to evacuate from bacteria, Erythroblast once again loses her way...