Percy Jackson 7 - Wrath of the Three-Headed Goddess

Percy is a senior, and when he wants to get into the University of New Rome, he needs three letters of recommendation from the Greek gods. He managed to get the first one from Ganymede. Now the goddess Hekate offered him another opportunity. All she has to do is watch her pets during Halloween week: the hellhound Hekabe and the polecat Gale. That sounds pretty simple, doesn't it?