McIver’s (Leigh My Amazing Son) rapidly paced fantasy tale follows fifth graders Leigh, Tara, and Cosmo as they combat corrupt land developers to save an underground world and the magical creatures that inhabit it. While visiting Cosmo’s idiosyncratic grandmother, the trio discover a forgotten mining system below her house, whose tunnels lead to a mysterious subterranean pool. As they explore the caves, they meet talking animals and encounter levitation enchantments that make it easier for Leigh, whose spina bifida necessitates use of a wheelchair, to navigate the craggy caves. When Cosmo’s grandmother informs the group that local property developers are looking to force her out, the middle schoolers take it upon themselves to save her house, and all of its magic, from destruction. Saunders’s cheerful illustrations, interspersed throughout, depict the characters’ whimsical adventures and various animal companions, such as badgers, bears, and mice. Though the plot employs standard fantasy tropes, the author develops the talking animals, labyrinthine tunnels, and ethereal magical atmosphere with care. McIver’s author’s note details the tale’s inspiration. Ages 5–10. (Self-published)