This is Halloween - The Great Holiday Mystery

Ah, Halloween. The spookiest time of year, filled with evil spirits and monsters. Perfect for the demigods, no?

This year, Annabeth, Hazel and Piper have successfully convinced Chiron that a Halloween party is a brilliant idea! With the three girls in charge and the rest of the seven under their command, they're determined to make this the best Halloween ever.

But alas, they are not destined to enjoy this holiday. 

The festivities turn out to be more deadly than they could ever have imagined. There's a mysterious intruder, and its taking them out, one by one. With everyone in costumes, can the demigods ever hope to find out who the perpetrater is? Or is it already too late?

DISCLAIMER: The characters in this book all belong to Rick Riordan and I only own the plot, which I beg of you not to steal. I dedicate this book to my best friends (with me and across the world) who know who they are.