This interesting dystopic series opener from debut author Hall follows the fortunes of Rachel, whose mother, Vivian, is “Gainfully Employed” by Ms. Moore, owner of an orchid business, a “Private Enterprise.” They live close to “the Line,” the border of the Unified States, and everyone fears what lurks in Away, across the Line. Vivian homeschools Rachel to insulate her from the lies of the repressive U.S. government schools, and Rachel does her best to help her cherished Mom, but she really loves working in the greenhouse, even if the severe Ms. Moore frightens her. However, when a boy appears across the Line asking for help, Rachel and the entire complex become embroiled in activities that might get them all arrested. The author trims her prose for an upper-elementary audience, but the story easily can appeal to teens. Without any hint at current politics, she encourages young readers to think about the tension between freedom and security while keeping them engrossed in a suspenseful story. Well done indeed. (Science fiction. 10 & up)