Blossom, Queen of the Fairies, has disappeared, along with three powerful magical objects, the Book of a Thousand Spells, the Crystal Sphere, and the Whispering Wand, and Geronimo Stilton is once again called on to confront an evil wizard, rescue the Queen, recover the objects, and save the entire Kingdom of Fantasy.

On his way to the Grand Masked Ball and what promises to be a disaster of a date, Geronimo is once again whisked away to the Kingdom of Fantasy, and this time he must save the Princess of the Vanilla Fairies from an evil wizard who is using the pirate ship, Ship of Secrets, to gather magical objects to increase his power and take over the kingdom.

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.

The Harmony Stone has been stolen from the Crystal Castle, and without it the Kingdom of Fantasy is vulnerable to an ancient enemy, The Invisible Army; Geronimo, together with Queen Blossom's daughter, Winglet, embarks on a mission to find the ancient crown which will defeat the Invisible Army and restore harmony to the empire--but they must make it back to the Crystal Castle before it is overwhelmed by the enemy.