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

On summer vacation in Scotland, the Thea sisters are intrigued by a tapestry that is really a treasure map supposedly leading to a hidden alabaster garden where an ancient treasure is buried, and the story of Aurora Beatrix Lane, an adventurous explorer mouse--and when the tapestry is stolen they set out to find the treasure using the explorer's diary as a guide.

"In this fabumouse adventure, the Thea Sisters head to Alaska, where they're attending a conference held by an important ecological association. Their host and his family are native Alaskans, who show the mouselings their favorite games and activities. But soon there's trouble - the Thea Sisters discover that someone is upsetting the ecosystem by blowing up the ice with explosives! Can the Thea Sisters figure out what's going on and save the day?"--Publisher....

The Thea Sisters help their friend Beatrice get ready for the Summer Olympics.

While attending the Cuckoo Clock Carnival in Germany, the Thea sisters investigate the theft of a famous clock.

There is a crisis in the Starlight Kingdom, one of the fantasy worlds: its stars, powered by a special kind of stardust, are fading and may soon go out forever, leaving the Kingdom in darkness--so the Thea sisters and Will Mystery set out for Brightstar Castle to discover what is wrong, but first they must overcome the obstacles and challenges that the fairies are placing in their way.

"When the Thea Sisters' friend Bridget returns to Scotland for a family emergency, the five mice offer to help. And when Bridget goes missing, they have to rush to Scotland to find her! Along the way, the Thea Sisters encounter Celtic legends, cryptic messages, and hidden treasures on a trip that's full of surprises!"

When Will Mystery calls, the Thea Sisters answer the call because there is trouble in one of the fairy kingdoms: a dragon has been turning all the fairies' precious gems into stone, and wrecking havoc throughout the Crystal Kingdom--and it is up to the sisters to find out why the dragon is destroying this Kingdom and stop him before it is too late.

While the Thea sisters are at the excavation site of a dig at Hierapolis, Professor Brenninger unearths a series of priceless and very old figurines, but the Thea Sisters think the discovery may be a scam and investigate.

"When Colette invites her friends to come home with her to Paris for spring break, the five mice are delighted. While they're in France, they'll even get to attend Colette's fashion-designer cousin Julie's runway show at the Eiffel Tower! But soon after the Thea Sisters arrive, Julie's designs are stolen. Will the five mice be able to catch the thief in time to save the fashion show?"--P. [4] of cover.