Final Fantasy XIII takes place in a world divided into two main regions: Pulse and Cocoon. Cocoon is a floating world in space, protected from collapse by the power of the Fal'Cie, powerful, supernatural beings who control this world. In contrast, Pulse is a dangerous and hostile world, filled with deadly creatures, and is viewed as a "lower world" by the people of Cocoon. The story begins with Lightning (also known as Claire Farron), a strong-willed woman who must confront her own fate after she becomes entangled in the conflict between Cocoon and Pulse. Her sister, Serah Farron, is turned into an L'Cie—someone cursed to carry out a mission that they cannot avoid, with uncertain consequences.  Their mission is to attempt to break the curse of the Fal'Cie, which has determined their fates, and to prevent the collapse of Cocoon, which could have catastrophic consequences for both worlds.