Comic horror provides adventure and a chance to save the world to 13-year-olds Charlotte and Zee. Charlotte has always been careful to remain unremarkable. She has few friends but few enemies, and does just well enough in school not to get in trouble. All that changes when her cousin Zee arrives from England. Zee is smart, polite, charismatic—and has been followed from England by a mysterious plague that afflicts kids in his vicinity with a terrible weakness. Charlotte and Zee are drawn into a conflict among the Greek gods for control of Hades; only by going down into the underworld can they heal the sick children. Though they rescue the children, unresolved questions lead the way into a second volume. Snarky wit and authorial asides, though occasionally intrusive, keep the adventure lively. A fun and funny tale of youthful heroism. (Fantasy. 9-13)