With a garbage thief on the loose in New Mouse City who is stealing organic waste, Hercule and Geronimo enlist the head of the Recycling Center to help, then discover that the thief has good intentions.

Creepella opens Mouse Island's first dating agency and hires Geronimo as her assistant, but someone is trying to sabotage their business.

When a celebrated goldsmith from Hawaii creates a necklace for a famous actress, rumors that the necklace is about to be stolen prompt Geronimo Stilton's investigation to identify the thief.

While celebrating his birthday with his family, Geronimo realizes someone has replaced all of his money with counterfeit bills and sets out to find the thieves.

When one of the helmets in Sven the Shouter's private collection is stolen, the micekings find their investigation complicated when the dragons attack.

Just as Creepella is about to interview Hector Spector, the owner of the Galloping Ghost Circus, strange things start happening around Cacklefur Castle, and she investigates.

When his cousin is captured by the king of the dragons, Geronimo must deliver the Crown of the Seven Rubies to free him.

"Moldy mozzarella! It was only a few days before Halloween when all of the pumpkins in New Mouse City disappeared. A thief was on the loose, and there was only one person I could count on to help me solve this peculiar mystery--my detective friend Hercule Poirat. But would we be able to figure out what was going on in time to save Halloween?" -- p. [4] of cover.

"My sister Thea and my cousin Trap were not getting along! When Grandfather found them arguing over who would get to join me on a trip to Brazil, he forced us all to go together. My friend Isabela needed my help finding a mysterious emerald. Could Trap and Thea stop shouting their snouts off long enough to help find the stone?" -- Back cover.

Geronimo Stilton is invited to a rat-jitsu martial arts championship in a snowy faraway land, much to the famouse reporter's surprise. With his helpful relatives, Thea, Trap and Benjamin, Geronimo goes to cover the event for the Rodent's Gazette. But something strange is happening. After each championship match, the winner disappears without a trace! Will Geronimo get involved and solve the mystery of the missing martial artists? Or will he be consumed...