Greenwich, Connecticut. Just a few days left before Halloween, everyone at Howard Academy is anticipating gorging on Harriet Bloom's famous marshmallow puffs. The private school’s annual costume party revolves around the headmaster's assistant and her seemingly supernatural batches of gooey goodies. When Harriet's elderly neighbor is found dead with the beloved dessert in his hand, police question whether Harriet modified her top-secret recipe to include a hefty dose of poison. Melanie Travis knows that, on an evening ruled by masked revelers, bizarre getups, and hidden identities, Halloween might just be the perfect opportunity for a cold-hearted killer to get away with murder once again. -- adapted from jacket.