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.

An all-new hardcover adventure featuring Thea Stilton and the Thea Sisters!At the beach by Mouseford Academy, one of the Thea Sisters discovers a mysterious boy with blue skin washed up on the shore. He speaks an unfamiliar language, so the Thea Sisters call Thea Stilton to help figure out how to communicate with him. She sets the mouselings on an exciting journey across the world to hunt for clues about the boy's origins. Could he be prince of the...

Violet has been chosen to play in the orchestra for a production of Romeo and Juliet in London! The mouselets begin to notice strange things happening during rehearsals. Someone is trying to sabotage the production. Can the Sisters uncover the phantom before the show is ruined?

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.

It is up to the Thea sisters to investigate when an Ecuadorian chocolate factory known for its environmental practices begins malfunctioning and the owner suspects sabotage.

The Thea Sisters are just about to head off on their separate family vacations when they receive a call from Will Mystery. Once again, there is trouble in one of the imaginary kingdoms! A crack has been discovered in one of the maps in the Hall of Roses. The girls head to the Crystal Kingdom to help uncover the mystery. There, they find that a dragon has been wreaking havoc all over the land. He has been turning all of their precious gems into stone...

The students of Mouseford Academy are participating in an enormouse science fair! Mice from schools around the world are all hoping to take the top prize. The Thea Sisters would love to win, but so would Ruby Flashyfur and she's willing to do whatever it takes! Can these mice play nice, or will the science fair be a total flop?

The Thea Sisters are visiting friends at a lively festival in Spain. But the theft of a precious fan turns their trip into an investigation! They end up hot on the trail of a secret treasure . . . but they're not the only ones searching for it. Illustrations.

"Mouseford Academy is planning a spring field trip to the waterfallin the forest, but angry bears are chasing people! Something strange is going on-- could Vissia de Vissen be up to her nefarious tricks again? If Colette, Nicky, Pamela, Paulina, and Violet don't figure out what's happening, the whole forest could be turned upside down. But not even Vissia de Vissen can steal a waterfall-- can she?"--Page 4 of cover.

"The Thea Sisters are heading to Rome! They were chosen to be part of an international archaeology competition. The mouselets have to follow clues through Rome to solve puzzles and win the golden cup. But as they explore the beautiful city, the sisters get the sense they are being followed, and worse, someone is going through a lot of trouble to slow them down. can teh mouselets figure out who is trying to sabotage their chance at the prize before...