The novel unfolds during Percy’s senior year at Alternative High School in New York — after the action of The Heroes of Olympus, but before The Trials of Apollo. This time around, Percy is not worried about saving the world. He has a much harder quest: getting into college. New Rome University requires recommendation letters from three gods, which means . . . yep, you guessed it. Percy has to run quests to get the letters. (That sound you hear is Percy screaming into his pillow in frustration.)

First quest: the cupbearer of the gods, Ganymede, is missing his chalice. Not only is this embarrassing. It’s also a potential disaster since any mortal who happens to drink from the cup will gain immortality. Percy, Annabeth, and Grover have to find that chalice and return it to Ganymede before anyone realizes he lost it. These gods . . . they really need GPS tags on their magic items, don’t they?

In the second of three quests Percy must complete to earn college recommendation letters from the gods, he has to pet sit the goddess Hecate’s polecat and giant mastiff during Halloween week. What could go wrong?

Percy Jackson, now a high school senior, needs three recommendation letters from the Greek gods in order to get into New Rome University. He earned his first one by retrieving Ganymede’s chalice. Now the goddess Hecate has offered Percy another “opportunity”—all he needs to do is pet sit her mastiff, Hecuba, and her polecat, Gale, over Halloween week while she is away. How hard could that be?

Percy, Annabeth, and Grover settle into Hecate’s seemingly endless mansion and start getting acquainted with the fussy, terrifying animals. The trio has been warned not to touch anything, but while Percy and Annabeth are out at school, Grover can’t resist drinking a strawberry-flavored potion in the laboratory. It turns him into a giant frenzied goat, and after he rampages through the house, damaging everything in sight, and passes out, Hecuba and Gale escape. Now the friends have to find Hecate’s pets and somehow restore the house, all before Hecate gets back on Saturday. It’s going to take luck, demigod wiles, and some old and new friends to hunt down the animals and set things right again.

Rick Riordan’s newest Percy adventure is full of hilarious set pieces, a diverse cast of gods and monsters, and many other delightful tricks and treats.