Who is Geronimo Stilton? That's me! I run a newspaper, but my true passion is writing tales of adventure. Here in New Mouse City, the capital of Mouse Island, my books are all bestsellers! My stories are full of fun - tastier than Swiss cheese and tangier than extra-sharp cheddar. They are whisker-licking-good stories, and that's a promise! Do you like solving mysteries? I do! So when my sister, Thea, heard that there was a secret hidden in Mouse Island's most famouse painting, the 'Mona Mousa', I knew we had to crack the code! We began to investigate, and soon we were following a trail of clues that led us below the streets of New Mouse City. There we made the most fabumouse discovery ...