When you're with Geronimo Stilton, it's always a fabumouse adventure! Geronimo is celebrating his birthday! He is out with his family when he realizes someone has replaced all of his money with counterfeit bills. Geronimo and Hercule set out to find the thieves!

After celebrating their first nine same-day birthdays together, Amanda and Leo, having fallen out on their tenth and not speaking to each other for the last year, prepare to celebrate their eleventh birthday separately but peculiar things begin to happen as the day of their birthday begins to repeat itself over and over again.

While trying to spare Erica's feelings so she could go to Brittany's birthday party, Allie disobeys one of her own rules and lies.

"It's bad enough Ian Barker has to spend his twelfth birthday with his sister and their two annoying cousins. The four of them can't ever hang out without getting into trouble. Vinnie and Jonny always want to play with Ian's stuff. They take extra turns and break everything they touch. Even Ian's new birthday presents are up for grabs. But when Ian gets a Slappy dummy from his dad, things go from bad to worse. When Slappy's in charge, you don't fight...

Victoria Torres has always had a family birthday party that she shares with her beloved grandmother, but this year she is so impressed by her classmate's birthday party at GlamaRama, the mall's newest spa store, that she decides that she wants to celebrate her twelfth birthday there--and her mother refuses to do both.

It's Nikki's birthday, and it is up to her whether it is a blast or a bust.