The Thea Sisters are taking a trip to Canada! They have been invited to do some bird-watching with a group of friends. The girls are enjoying learning more about Canada and their love for hockey. But during their trip, one of their group members mysteriously disappears. They set off to Niagara Falls to find him. Can they solve the mystery?

When a member of their group goes missing, the Thea sisters head to Niagara Falls to find him.

The Thea Sisters are taking a trip to Canada! They have been invited to do some bird-watching with friends. The girls are enjoying learning more about Canada and their love for hockey. But during their trip, one of their group members mysteriously disappears. Can they solve the mystery?

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!

Join Thea Stilton and the Thea Sisters on this adventure packed with mystery and friendship! The Thea Sisters are in Kenya on a photo safari! The mouselets love exploring the magnificent landscape and learning about the animals on the reserve they're visiting. A lion cub has just been born -- but while they're there, he's kidnapped! It's up to the Thea Sisters to rescue him in an adventure across the savanna.

The Thea Sisters are headed to Venice, Italy! They'll be there for the Carnival, an annual festival that's famouse for its elaborate masks. They mouselets love exploring the city's bridges and canals, and seeing the beautiful costumes mice wear to Carnival celebrations. But a mysterious thief strikes while they are there! Can they catch and unmask him before the festival ends?

Join Thea Stilton and the Thea Sisters on an adventure packed with mystery and friendship! The Thea Sisters solve a mystery in the Black Forest!

Join Thea Stilton and the Thea Sisters on an adventure packed with mystery and friendship! One of the Thea Sisters' favorite authors, a famouse mystery writer, has disappeared! To find him, the five mice travel to his native Iceland. Together they traverse the stunning landscape and reconstruct the plot of the author's latest novel. But it's more dangerous than they expected! Can the mouselets locate their beloved author, or will their search just end up as an icy mess?

Join Thea Stilton and the Thea Sisters on an adventure packed with mystery and friendship! The Thea Sisters are in Russia for a figure skating championship! When their new friend is falsely accused of theft and barred from competing for the gold medal, the five mice resolve to clear her name. Along the way, they discover ancient love letters that could be the key to finding the real culprit! But can they solve the mystery in time?

Join Thea Stilton and the Thea Sisters on an adventure packed with mystery and friendship! The Thea Sisters spend the holidays in Rome!