In Hollow Lands — Sophie Masson

Ti-Korriganed loomed up, the great grey stones rising in the dimming light like huge, cowled shadow-figures. The owl was sitting by the tallest stone. But there were other creatures, all with that strange restlessness, that edgy melancholy quick-to-anger of the otherworld.Lured into the world of the magical korrigans, the young twins, Tiphaine and Gromer, may never break their enchantment. But Tiphaine's bright mind sees that not only korrigans may discover hidden powers within themselves. In the human world, young Bertrand du Guesclin fights in the wars — until, in a strange wood, he senses the dangerous presence that will transform his life.Reading one of Sophie Masson's books is like standing on top of a lonely mountain at midnight, under a star-filled sky... Her work has that same sense of clarity, magic, and mystery...—Garth Nix