Final Fantasy XIII takes place in the fictional floating world of Cocoon, whose government, the Sanctum, is ordering a purge of civilians who have supposedly come into contact with Pulse, the much-feared world below. The former soldier Lightning begins her fight against the government in order to save her sister who has been branded as an unwilling servant to a god-like being from Pulse, making her an enemy of Cocoon. Lightning is soon joined by a band of allies, and together the group also become marked by the same Pulse creature. They rally against the Sanctum while trying to discover their assigned task and whether they can avoid being turned into monsters or crystals at the completion.