In the human body even daily work can be life-threatening. Faced with dangerous incidents once again, among them Malaria, caused by a red blood cell destroying parasite, both AE 3803 and U-1146 finally begin to grasp something about their relationship. The other neutrophils, U-4989 especially, have noticed this too and are eager to help them along...preferably without the two noticing them meddling.

Keegan is a boy who loves affection. He's usually quite peppy and excitable, but everything in life has turned against him. He ends up locking away his emotions and making himself distant from the world, trying to avoid further suffering. He's left a shell of his former self, struggling to get through life. He decides to take time away from his abusive life by going on a week long school trip to collect his thoughts. He is placed in situations he couldn't have imagined. Theo is a laid back jock. He can come off as aggressive and bossy, usually around his friends, though he has a heart and can be quite kind. His life is hectic and full of annoying people. His parents are inconsiderate, his friends are clingy and loud, and the rest of the school sucks up to him, which he doesn't received well. He just wants to be left alone. After deceiving his clingy friends he snuck away on the school trip, hoping he could finally get some peace and quiet. This trip would hold some surprises for him, and maybe even change his life. What future will await these two? Are they destined for greatness, or despair?