It is Halloween night and all the kids are dressed in scary and funny costumes. Their Trick and Treat bags are getting heavier.
Nate's good friend Rosamond needs his help. Her cat Little Hex is missing. Little Hex hates Halloween, so maybe he's hiding. Or is he lost?
Nate and his trusty dog, Sludge, take the case and hunt in the night for Little Hex. They pass robots, pirates, and witches. But where will they find Little Hex?

"All the regulars are back in Nate's latest mystery, and as fresh as ever. Sharmat makes beginning to read a pleasure."