When Will Mystery calls, the Thea Sisters answer the call because there is trouble in one of the fairy kingdoms: a dragon has been turning all the fairies' precious gems into stone, and wrecking havoc throughout the Crystal Kingdom--and it is up to the sisters to find out why the dragon is destroying this Kingdom and stop him before it is too late.

"Original title: Il segreto delle fate dei cristalli." "Illustrations by Giuseppe Facciotto, Chiara Balleello, Barbara Pellizzari, Valeria Brambilla, and Alessandro Muscillo." "Based on an original idea by Elisabetta Dami."