The Chocolate Chase by Geronimo Stilton

There was a choclate egg that got stolen from the museum. There was a small blonde hair and only a pure diamond can cut through the glasslid of the egg case. Geronimo Stilton is a news mouse reporter, he used his nose to smell the scent that the egg theif had. After finding the thief Geronimo found out what the thief was using the egg for. She was using the egg to win the chocolatiest egg contest.