You can choose your friends, but you can't choose your primas...
Luna Ramos has more cousins than she can count, and even though her mom says that makes her lucky, Luna knows that every time she gets in trouble, one of her primas is responsible. But when Luna locks her know-it-all cousin Claudia in the bathroom at their cousin's quincean᷈era, Luna has no one to blame but herself. Her punishment? No hats for a whole month - which is a big deal because Luna's always been embarrassed by her hair, and hats make her feel more comfortable.
To make things even worse, Claudia is transferring to her school, and now she'll have a chance to tattle on Luna even more than she already does! Her grandmother offers some sage advice, but since it's in Spanish, Luna gets it all wrong, and when the kids at school begin making fun of Claudia, Luna must decide what matters more: family or her reputation.