Geronimo's adventurous sister Thea takes center stage in this super special that's packed with mystery, adventure, and friendship!When Geronimo's sister, Thea, is invited to teach a journalism class at a college on Mouse Island, she has no idea that she's going to be called on to help solve a mystery. But when a student disappears, it's up to Thea and five of her students to find out what happened. A nail-biting mystery ensues, complete with secret passages, underground tunnels, and more than a few surprises along the way. Readers will love following the clues to help Thea and her new friends through their first adventure together!

When you're with Geronimo Stilton, it's always a fabumouse adventure! 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?

Thea Stilton and her journalism class try to find a missing student.

Geronimo's adventurous sister Thea narrates this fabulous adventure that's packed with action, mystery, and friendship!Thea's friends the Thea Sisters take off for Australia to solve a mystery. A flock of sheep at Nicky's family's ranch is losing all its wool, and the ranch depends on the wool to stay afloat! Maybe the sheep's cure lies in an Aboriginal medicine containing a strange root. The five mouselings set off on a tour of the whole country to find out. It's a truly memorable outback adventure!

Join Thea Stilton and the Thea Sisters on an adventure through Mouseford Academy! There's going to be a musical at Mouseford, and the Students can't stop squeaking about it! Everyone wants a role, but the auditions won't be easy. Plus, sneaky Ruby Flashyfur has some tricks up her sleeve.

Geronimo's adventurous sister, Thea, narrates this fabulous adventure that's packed with action, mystery, and friendship!During a marine biology lesson at Mouseford Academy, the Thea Sisters learn about a mysterious shipwreck off Whale Island. According to legend, a very rare diamond called Jasmine's Heart was on the ship when it sank. When biology teacher Professor Van Kraken disappears, the Thea Sisters have to dive into the deep ocean to find him and the jewel. And just when they think their adventures are over, the Thea Sisters receive an invitation to travel to China to find another missing treasure. It's an adventure these five world-traveling mice will never forget!

Thea, Geronimo's sister, is invited to a college on Mouse Island to teach a journalism class, and when a student disappears, Thea and five of her students go on an adventure to solve the mystery.