Melanie Gate is a foundling with a peculiar talent for opening the unopenable—any lock releases at the touch of her hand. One night, her orphanage is visited by Traveler, a gearling automaton there on behalf of his magical mistress, who needs an apprentice pronto. When Melanie is selected because of her gift, her life changes in a flash, and in more ways than she knows—because Traveler is not at all what he seems. But then, neither is Melanie Gate.