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 has been assigned to train a rookie Red Blood Cell! She resolves to “show her what a dependable senpai I am!” But she keeps losing her way, and getting yelled at by other cells, so it’s not going very smoothly. Just then, a major incident rocks the world inside the body.

Memory Cell sees a dream where the arrival of messengers from the outside signal the end of this world... As if his dream became reality, unidentified enemies enter the body! Does Memory Cell not only have the power to remember the past, but also predict the future now? Will this world be ruined as Memory Cell predicts?

Ordinary Cell heads to the intestines with White Blood Cell (Neutrophil) to reunite the lactic acid bacteria with their friends, but they get separated from one of the bacteria on the way there. Ordinary Cell desperately searches for the lactic acid bacterium but is attacked by cells infected by a new virus!