Reaching a compromise with her parents when they say she is too young to attend a concert alone, Mia discovers that she is being cyberbullied on social media and teams up with her fellow Cupcake Club members to discover who is behind the attacks.

"Mia is having a terrible day! Everything is going wrong. She woke up late and couldn't make her hair look perfect or brush her teeth, she probably failed a pop quiz, and she broke her glasses! But when her mom's cousin Laura arrives from Puerto Rico, she gives Mia a bracelet with a lucky charm. All of a sudden, Mia's luck changes for the better. Mia's thrilled--she'll never have a bad day again--or will she?"--Back cover.