As the series progresses we are gradually revealed the history between Nanako and Ogami's family and given a reason why the two are so tightly knit together, as well as why the title refers to Nanako as a "nurse". A minor supporting cast is introduced, though Nanako and Ogami are clearly the leads. The plot incorporates the American military, the Catholic Church and outlandish science fiction experiments, with these elements progressed mostly in the lead episode and the last two episodes. The middle episodes 2-4 feature mostly unrelated one-shot plots, though minor progress is made in each episode regarding the history between Nanako and Ogami's family.