The characters soar in this thoroughly metaphorical fantasy from newcomer Holch. Tracking the millions of Emerald Rainbow butterflies that migrate each year through the small town of Angel Falls, young Newton and his new friend, Vanessa, find a walled garden containing portentous signs--""More is hidden than visible,"" ""Everything that grows must change,"" etc.--and a certain tree pulsing with butterflies. When Vanessa samples the tree's fruit, she is transformed into a caterpillar that can eat only books: The diet horrifies her, but after a short pupation she has temporary wings and a permanent ability to fly. Exultantly, she snatches Newton up for a flight over the countryside, only to spot many of her classmates caged in caterpillar form and starved to prevent their metamorphoses. Who has done this? Their parents, many of whom once flew but through fear, guilt, or lack of interest have forgotten how, want to keep their children grounded. Holch's simple, direct style and his pairing of young people with vastly different but complementary characters is reminiscent of Kevin Henkes's novels, but there are contrivances: An adult in mirror shades has an ominous interest in Vanessa until it comes out that he's her father; they suddenly move away for no clear reason; Newton re-enacts an old Chinese story, dreaming of being a butterfly and waking to wonder which is the dream. Despite such convolutions, readers will devour the story, and hope for more fantasy musings from Holch in the future.