For fans of Nevermoor and Howl's Moving Castle comes an epic middle grade fantasy about a girl with the ability to unlock anything--including the empire's darkest secrets.

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 lifeless 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.

So begins an epic, overland adventure sparkling with magic, secret identities, stinky cats, fierce orphan girls, impostor boys, and a foundling and gearling hotly pursued by the most powerful and dangerous wizard in the land. Along the way, Melanie never expects to uncover the source of her own true powers—or learn that she may be the key to saving the empire.