The body has been invaded by a mass of cedar pollen! Rushing to the scene so that he can eliminate the cedar pollen, White Blood Cell (Neutrophil) runs into Memory Cell. Memory Cell is a Lymphocyte who retains the immune system’s memories. Seeing what’s actually going on, Memory Cell is strangely flustered. “What the heck? This is just like the legend...” What “legend” is Memory Cell talking about?

Red Blood Cell is being chased by a germ! The one to come to the rescue is a masked Monocyte. Apparently, they are also part of the White Blood Cell family and a type of Immune Cell. There’s no way Red Blood Cell could be attacked by bacteria twice in one day, but she encounters another one on her way to the nasal cavity. The germ turns out to be Staphylococcus Aureus. They usually just exist on the skin and pores. But this time, they have a secret plan. What could it be?

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."