The Princess Diaries: Prom Princess (Book 5)

Princess Mia Thermopolis is about to turn fifteen - and can't wait to dance the night away with Michael at the biggest, most romantic event of her life so far: the senior prom! But nothing's going according to plan. Not only does Mia face a snoozefest summer of public functions in Genovia. Even worse is the fact that Michael hasn't even invited Mia to the prom at all. Hello, what is going on here? Just as Mia comes up with a perfect plan to change her man's mind, disaster strikes. A disaster that only a (slightly-evil) genius like Grandmere can overcome...