Hubert Van Harwoerst, member of the renowned dutch academy of master cheese-makers is under constant attack at his Edam factory on the outskirts of Rotterdam from a plague of grebes. The birds swoop down on the factory and grab a cheese, then fly off before Mr Van Harwoerst can stop them. However, the problem does not stop there. When the grebe reaches 32,000 feet, the Edam implodes, causing a small hole to appear in the space-time continuum, from which space worms crawl and devour the unfortunate grebe. The space worm is a highly unstable creature, and within five minutes of its appearance it breaks down into a whirling vortex. This is the cause of so-called Clear Air Turbulence, which causes many problems for pilots.