Fourteen-year-old Mia, who is trying to lead a normal life as a teenage girl in New York City, is shocked to learn that her father is the Prince of Genovia, a small European principality, and that she is a princess and the heir to the throne.

Mía, una joven adolescente neoyorquina ve cómo su vida cambia de la noche a la mañana cuando averigua que es la futura heredera de Genovia, un diminuto país europea. Having recently discovered she is the sole heir to the throne of a tiny European principality, fourteen-year-old Manhattan resident Mia writes in her journal about her attempts to cope with this news, as well as with more typical teenage concerns.