I am not the kind of mouse who spends money on useless things. But one day I kept getting packages of things I did not order or need. Someone on the Internet had stolen my identity! Professor Margo Bitmouse, a well-known computer expert, helped me track down the hacker. Could I find the thief before my reputation was ruined?

Geronimo Stilton is the bestselling series for children by Edizioni Piemme, Milan, Italy. The English version of the books was published by Scholastic Corporation. Geronimo Stilton is the title character of the book on whose pseudonym the books are published. This idea was originally developed by Elisabetta Dami.