Pickax loves a big occasion. The Great Food "Explo" is about to begin, introducing new restaurants, country inns, and food specialty shops. Lurking in the background, though, is a killer determined to make this an event Pickax City will never forget.

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.