This book is about when Sally Ratmousen hired Sydney Starfur to be Geronimo Stilton so that Sally Ratmousen could steal the Rodents Gazzete .People kept telling these horrible story's and the real Geronimo knew he never did that. He found out what Sally Ratmousen was planning. So Geronimo did the same as Sally Ratmousen and used Trap to be Sally Ratmousen.