In this graphic non-fiction, the Medikidz zoom to Earth to get Jo, a girl with a brain tumor.  They bring her back to Mediland with them and similar to the Magic School Bus, they shrink and travel into a brain to see how brains grow and function.  Jo learns that when cells start to multiply and behave badly, they lump together to form a tumor which can display symptoms and can be either benign or malignant.  Treatment and after effects of such are also explained.  Graphics are interesting, the information is great without any emotional attachment, and there is nothing gloomy about it.  I enjoyed learning about brain tumors.