Geronimo Stilton, top reporter for The Rodent's Gazette, keeps has a reputation of breaking the top news stories first to the citizens of New Mouse City. But lately, Sally Ratmousen of rival Paper 'The Daily Rat,' has been leaking Geronimo's secret scoop! Can Geronimo keep the lid on a surprise celebrity guest to the city's 100 year celebration or will Sally rat him out?