Eel, an orphan, and his best friend Florrie must help Dr. John Snow prove that cholera is spread through water, and not poisonous air, when an epidemic sweeps across their London neighborhood in 1854. Interest Level: 5-8 Reading Level: 4.2 ATOS Book Level: 4.6 AR Interest Level: MG AR Points: 7 AR Quiz: 161212EN Reading Counts Level: 3.8 Reading Counts Points: 11 Lexile Measure: 660 Fountas & Pinnell: X Iowa Children's Choice 2015 -2016.