"El Libro de Piedra" or "The Book of Stone" is a Mexican horror movie. In it, Julia has just been hired to be the governess of a girl named Sylvia who lives with her father and step-mother. Sylvia doesn't have a good relationship with either of them. She also claims to play with a boy named Hugo -- who appears to be nothing more than a stone statue in the courtyard. Strange and horrible things start to happen, and they lead the adults to wonder how imaginary Sylvia's playmate is.