Resume : The story follows the world of a human's body which is represented as cities with roughly 37.2 trillion anthropomorphic cells who work together endlessly daily to run their world. Everyday, they struggle to remove and resist against pathogenic cells such as germs and bacteria from invading the body.

The main focus is largely on two such cells; a rookie red blood cell, AE3803, who often gets lost during deliveries, and a relentless white blood cell, U-1146, who fights against any germs that invade the body.