Thea Stilton and the Thea sisters are on an expedition to the fantastical land of Erin. While searching for a missing friend, they learn that the land itself is in peril! The mouselets are ready to help.
On their journey, they encounter fairies, pixies, and other magical creatures - some helpful, but some out to trick them! Can the Thea sisters save the land of Erin before it's too late? It's an adventure full of mystery and friendship!
