Unpopular schoolgirl Jenna Rink makes an unusual wish on her birthday. Miraculously, her wish comes true and the 13-year-old Jenna wakes up the next day as a 30-year-old woman.
Mia Thermopolis has just found out that she is the heir apparent to the throne of Genovia. With her friends Lilly and Michael Moscovitz in tow, she tries to navigate through the rest of her sixteenth year.