A magical, steampunk fantasy adventure by international bestselling authors Rebecca Moesta and Kevin J. Anderson. Teenaged cousins Gwen and Vic are whisked through a dimensional crystal door to a fantastic island kingdom where they have to learn both science and magic to fight in a war against an undersea empire. They and their companions, all assembled from other worlds accessed through the network of Crystal Doors, hold the key to saving this exotic universe—and all others. They must battle the monstrous forces of the evil wizard Azric on land, sea, and air.
Contains the three complete volumes: Island Realm, Ocean Realm, and Sky Realm.