The Expo begins with a literal bang: a bomb wrecks the hotel, killing a housekeeper and causing extensive damage. Luckily for Pickax, Jim Qwilleran is on the scene, with suspicions that the bomb was intended as something stronger than a warning to someone. His evidence: Koko and Yum Yum's new interest in cheese, especially Gruyere, Brie, and Feta. Qwill and the Siamese are on a case that will demand all of his insight as well as their feline intuition.