From the back of the book:
Flexible RPG systems like Fate Core are terrific if you have the time and energy to put into building a world. But we also realize that sometimes extensive prep just isn't feasible. The good news? You can still experience the Fate awesomeness with the help of the Fate Worlds expansion.
Fate Worlds Volume 1: Worlds on Fire is the first in a two-volume set. In Worlds on Fire, you get six rich story settings. Each setting includes custom mechanics, NPCs, and story elements—all ready to go using the system provided in Fate Core. We've got you covered regardless of your flavor of RPG choice. Divest an evil cult of a powerful idol in Tower of the Serpents, or experience the small town supernatural in White Picket Witches. Explore the lives, loves, and losses of fire fighters in Fight Fire, or take on a horde
of WWI mechanical monstrosities in Kriegszeppelin Valkyrie.
Whether you stick with one world or go on grand tour, Fate Worlds will provide everything you need to develop your Fate Core adventure except the snacks.
Fate worlds. All the worlds. Your stage.