Keeper of the Lost Cities

Keeper of the Lost Cities is a 2012 children's fantasy novel by Shannon Messenger, published by Simon & Schuster.

Sophie's problem is stated as a matter of fit. She has been advanced through school faster than her contemporaries and has no friends among them, and her difficulty with her own family is explained by the secret she is keeping: she can read minds, and she has assumed she is the only one who can. Meeting Fitz changes that assumption and also changes her position, since he tells her she was hidden among humans deliberately. Sophie is twelve and lives in San Diego with a human family, and the boy she meets tells her that she is an elf and that she has to move to the Lost Cities.

The novel then requires her to leave her family for a society that is unfamiliar to her, which is the movement the title describes. What she takes with her is a set of buried memories whose content is in demand, and the book's plot is the gradual recovery of an identity she did not know she had.