At night our mattresses become a community, teeming with a multitude of mites. They sometimes fight and devour each other. Some are predators, others pray, still other scavengers, thriving on dead skin. Looking like aliens, these parasites adapt to all elements : earth, air and even water.If some mites are notorious for causing disease and allergies, others are extremely beneficial. Mites are auxiliary policemen. By their presence and development phase they pinpoint the hour of a victim's death, providing precious clues before a full autopsy. Glenn is the world's largest producer of killer mites, dispatching 500 000 predators a day all over the world. This is a high growth business. But these new domestic pets are difficult to raise and a kilo of mites costs 100 times more than a kilo of gold!In the central highlands of France, the Auvergne-cheese-mites are called the cheese-makers. Locals say that God sent them to earth to keep gourmets happy. They give cheeses an incomparable savour to such an extent that in olden times they were eaten for breakfast, spread on bread. In just 40 days, a single pair of mites has nearly 100000 grand-children!For the first time, state of the art electronic microscopy technologies show us what has been invisible up until now.