Aimed squarely at Captain Underpants fans, this mixed-format romp introduces two lads who decide to solve their cash-flow problems by becoming fabulously rich authors like J.K. Rowling. Instead, they fall down a shaft into the counterpane Netherworld, where “Dr. Nietsneknarf,” DDS and his slobbery minion “Rogi” reveal plans to use their brains to create “boy-brain creatures—the world will no longer be safe from slackers and gingivitis! Ha!Ha!Ha!Ha!Ha!” Running into, and then away from, a werewolf, a vampire and several “graveyards with dead trees with blood and guts hanging off them,” Fred and Anthony make their way home accompanied by a ghost with literary pretensions. Expertly blending short blocks of text with pages from a Netherworld travel guide and quick-sketch cartoon panels, Primavera—or “Arevamirp”—never lets up on either the laughs or the helter-skelter action. A series kickoff with kicks galore. (Fantasy. 9-11)