Mia is being cyber-bullied, and she's determined to find out who is responsible in the latest addition to the Cupcake Diaries series. Mia is upset when her parents tell her she's too young to go to a concert without adult supervision. She's old enough to help run a cupcake business! Why can't her parents see that she's also responsible enough to do whatever she wants? And just when she's reached a compromise with her parents (her older brother Dan will go to the concert with her), Mia finds out she's being cyber-bullied on social media. It's the Cupcake Club to the rescue as they all help Mia solve her online bullying mystery!