Geronimo investigates the rumors of a secret hidden in Mouse City's most famous painting, the Mona Mousa, and follows a trail of clues which lead below the streets of New Mouse City.

Have you ever heard of Nostraratus, the famous Grand Master of predictions? He predicted, including the exact date, the end of the world! And I, Geronimo Stilton, I was to publish his manuscript, when something incredible happened during the Roquefort fair.

When Geronimo Stilton's work as editor of "The Rodent's Gazette" interferes with his vacation plans, the only place he can still get a reservation sounds like a disaster, especially when he learns who he will have to share with.

"Geronimo follows clues in a diary all the way to Mouse Everest in search of his old friend Professor von Volt who has mysteriously disappeared." --

When Geronimo's sister, Thea, discovers an old, mysterious map showing a secret treasure hidden on a faraway island, the gang of the "Rodent's gazette" is dragged into a treasure hunt.

A subway tunnel haunted by ghosts? Ace reporter Geronimo Stilton is on the case! When my sister, Thea, told me a ghost was haunting New Mouse City's subway tunnels, I knew I had to get the scoop! So Thea, Trap, and I set off to investigate. We soon discovered that my rival Sally Ratmousen, the editor of The Daily Rat, was also on the trail of the mysterious ghost. But holey cheese, we were all in for the fright of our lives - because the ghost turned...

Geronimo travels to Ratzikistan to help his grandfather write a travel guide about this remote area.