“The perfect series for fans of Rick Riordan’s Percy Jackson and the Olympians books.” —School Library Journal Two cousins venture into the Underworld to save their classmates from a mysterious illness in this “entertaining in the most pleasingly frenetic of ways” (Publishers Weekly) first book in the middle grade Cronus Chronicles series inspired by Greek mythology—now with a new look!Something extraordinary is about to happen to Charlotte Mielswetski. Oh, it’s not the cute kitten that appears out of nowhere. It’s not the sudden arrival of her cousin Zee, who believes he’s the cause of a mysterious sickness that struck his friends in England. And it’s not the men in tuxedos who follow Charlotte everywhere. What’s so extraordinary is not any one of these things. It’s all of them. And when Charlotte’s friends also fall sick, Charlotte and Zee set out on a quest to find a cure that leads them to the Underworld.