New York : Scholastic Inc., c2013.
304 p. : col. ill. ; 20 cm.
Translation of: Il segreto delle Fate del Lago.
"Based on an original idea by Elisabetta Dami."
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.