The Seven Roses, magical flowers which bloom forever and which are linked to the health of the Land of Flowers, are dying, and the Thea sisters together with Will Mystery must travel to that land to discover the reason--a journey where every flower seems determined to hinder their passage.
The Thea Sisters travel through Mount Everest to enlist the help of the magical creatures they encounter on their journey to the Cloud Castle, where they are investigating why the clouds are disappearing from the Land of Clouds.
Attending an adventure camp in Madagascar, the Thea Sisters enjoy learning about the region's exotic plant and animal species before discovering that someone has been stealing endangered animals from the jungle.
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!
When a performance of William Squeakspeare's favorite play Mouseo & Juliet is planned for the six hundredth anniversary of Mouseford Academy, the Thea Sisters and their rival Ruby all want the part of Juliet.
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 Thea Stilton travels to Ireland to search for a missing agent, she finds that the whole fantasy Land of Erin is being threatened by earthquakes, and soon Will Mystery and the Thea sisters follow to help her find the secret of the fairies.
The Thea Sisters are summoned to the Seven Roses Unit by Will Mystery, but when they get there Will is missing; the sisters follow a trail of clues to the Fantasy Kingdoms, and find out that the Mayhem Mirror has been disturbed, and a terrible curse is about to be unleashed on the Fantasy Kingdoms, and it will be up to them to find the eight Harmonies which can break the curse and save the Kingdoms.
Discovering that the turtles on Turtle Island have gone missing, the Thea Sisters spot environment-threatening drums of a strange oil and struggle to gather help before spotting a pair of turtles entering a mysterious underground cave.