The enemy disguising himself as a common cell has revealed his true identity. He is Cancer Cell. To protect this world, White Blood Cell (Neutrophil), Killer T Cell, and NK Cell must now confront the attacking Cancer Cell in battle.

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!

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."

The most formidable foe has returned... Cancer Cell has reappeared, and harmful bacteria are wreaking havoc in the intestinal environment. With the body being in unprecedented danger, White Blood Cell (Neutrophil) and his comrades fight a bloody war to protect the future of the world they live in.

"Stop it, Cancer Cell!" White Blood Cell (Neutrophil) and his comrades confront Cancer Cell, but Regulatory T Cell obstructs their fight against the enemy! Meanwhile, Ordinary Cell, who had risked his life to save lactic acid bacteria, finds himself in the clutches of harmful bacteria! What fate awaits this world and the cells that live in it?