Persephone & the evil king

"The sixth book in the Little Goddess Girls series, part of Aladdin QUIX, a line of fun-to-read, short chapter books for emerging readers. Persephone, Artemis, and Aphrodite are on a quest to save their fellow Little Goddess Girl, Athena, from the evil King Hephaestus. It turns out the king has turned Athena (and her dog, Oliver) into treasures, and have hidden them in a massive treasure room. The girls only have seven guesses as to what and whe...