Her first published work was a trilogy published in the late 1980s and early 1990s (The Spellkey, The Glass Salamander, and The Books of the Keepers), collected in a revised edition in 1995 as The Spellkey Trilogy. A second series for middle-grade readers, begun in 2003 with the novel Hatching Magic, continues with The Dragon of Never-Was (2006). The Spellkey series is high fantasy, taking place wholly in an invented world and chronicling a good-versus-evil story of two foundlings, a stableboy and an ostracized seer. Hatching Magic and its sequel, The Dragon of Never-Was, are contemporary fantasies with elements of time travel. The series follows a young girl, Theodora Oglethorpe, as she discovers a world of wizardry and magic. While Downer’s books are frequently compared to the work of Patricia A. McKillip and Diana Wynne Jones,[ she has cited the influence of Ursula LeGuin’s Earthsea books and the Chronicles of Prydain by Lloyd Alexander in shaping her outlook and prose style.