Searching for her lost sister, Lillian finds a lost world... Joined by her best friends, Katy and Maisy, Lillian must cross a sea guarded by Krakens and sirens, race through a dark forest haunted by elves and chimeras, and trek over mountains ruled by griffins and rocs. Where in this world is Lillian’s sister? Who is the mysterious boy with the stone medallion? Why do the monsters hold an ancient grudge against humanity? And what is the secret, hiding at the heart of it all, that could change the world forever?