Geronimo isn't the only world-famous adventuring journalist from New Mouse City; introducing his fabulous sister, Thea! The Thea Sisters are five fun, lively students at Ratford College on Whale Island, who want to be real, live journalists just like their hero, Thea Stilton. Between classes and friendships, love and small fits of jealousy, they're finding college life is really exciting! In "The Secret of Whale Island," it's the start of the new school year and the students have arrived at Ratford College. Every year at this time, the whales move off the coast of Whale Island, but this time, a savage killer whale threatens the peace.

It’s election time at Ratford College and the candidates from the Lizard and Gecko student clubs face some challenges if they want to get elected president. Certainly not helping matters is the arrival of a mysterious black ship off the shores of the island . . . and it’s trying to pollute the beach! The girls must use all their investigative skills to root out the connection between the ship and the campaign. The fates of the election and their beautiful island home is at stake!

Get ready for more exciting adventures with Colette, Violet, Pamela, Nicky, and Paulina on Whale Island! In The Treasure of the Viking Ship, the team investigates an ancient archeological discovery, then in Catching the Giant Wave the island is threatened by a freak accident of nature!

A new, exclusive surfing club has just opened on Windy Island. Residents know that the island is famous for its sudden storms, but their warnings fall on deaf ears until a giant wave hits.

The Thea Sisters are five fun, lively students at Mouseford Academy on Whale Island, who want to be real, live journalists, just like their hero, Thea Stilton. Between classes, friendships, crushes, and some bizarre mysteries to solve, they find life to be a never-ending adventure!

During a hot-air balloon flight, the Thea Sisters discover that the turtles have vanished from Turtle Island! If that wasn't alarming enough, dangerous drums of a strange oil are spotted off the shore of the island-a disaster waiting to happen! The Thea Sisters are surprised that none other than Vissa De Vissen wants to help them save the island and the turtles! All seems lost until Nicky and Paulina spot a couple of turtles entering a mysterious underground cave! There are mysteries within mysteries, but the Thea Sisters are determined to solve them all and save the day.

Great news for the Mouseford Academy students! Top Direction, one of the most popular bands for teenagers, is going to perform on Whale Island! And they have decided that the opening act will be chosen among the best bands Mouseford Academy has to offer! Students have two weeks to write a song, and then Top Direction will pick the winner. The Thea Sisters have to win, but someone is trying to sabotage their performance. The Sisters must work together to find their sound, write a great song, and put on the performance of their lives.

Great news for the Mouseford Academy students! Top Direction, one of the most popular bands for teenagers, is going to perform on Whale Island! And they have decided that the opening act will be chosen among the best bands Mouseford Academy has to offer! Students have two weeks to write a song, and then Top Direction will pick the winner. The Thea Sisters have to win, but someone is trying to sabotage their performance. The Sisters must work together to find their sound, write a great song, and put on the performance of their lives.