Cervera, Spain, 1852. David Sandoval is a sixteen-year-old genius on many different subjects, yet he is more content studying than becoming close with family or friends. When he accepts an apprenticeship offer from a French architect, he is convinced that this will be the biggest achievement of his life. While on his travels to Paris, a foolhardy decision on his part gets him abducted by a gypsy caravan, owned by a living Grecian sphinx. The sphinx, seemingly intrigued by the fearless young man, takes him through the Curtain, the gateway between our world and the worlds of the "unseen," where many creatures of myth and legend reside. When David discovers that he has unwittingly proposed to the sphinx - who appears pleased to have him as a potential mate - he attempts to escape back through the Curtain to the human world, only to be sent to Kyoto, Japan, and that is only the beginning of his problems. On his adventure to return home, he learns a dark secret: a Shade, an extension of the shadowy Night Goddess Nyx, is slowly draining the sphinx of her most precious talents. David might be the only human on earth with the knowledge of how to save the sphinx from a lethal blight imposed on her by Nyx, and he must also save his new friends from a ruthless adversary, the Teumessian. Can one normal boy truly undo the inflictions of a goddess, and rescue both the seen and unseen worlds from her dark intentions?