Newspaper editor Geronimo Stilton resides in New Mouse City the capital of Mouse Island with his relatives. After they travel to England they discover their cheese is missing and now they must spend their time searching for the thief who stole it.
In 1801, in Chesire, Massachusetts, Elder John Leland organizes his fellow townspeople to make a big cheese for President Jefferson who up until that time had been forced to eat inferior cheeses.
When the wonderful, smelly, scrumptious cheese made once a month out of the milk of a one-horned, two-eared, three-legged cowabunga is stolen from the dell, Sherlock Bones is enlisted to find out what happened.