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.

The antibody information of a cell has leaked. There is tension in the air after NK Cell makes a comment to White Blood Cell (Neutrophil). The journey to reunite the lactic acid bacteria with their friends takes the group to the large intestine. In the intestine, which has been irritated due to toxic gas being released by harmful bacteria, the group meets up with Memory T Cell who was formerly known as "Killer T Cell."