Lightning Returns: Final Fantasy XIII is the third episode in the Final Fantasy XIII saga. It follows the story of Lightning who returns after a long period of time, having to fight her way through against various foes and even allies because of a prophecy predicting that the Savior will return to destroy the world. The game must be completed in a limited amount of time, seven days that can be extended to thirteen days. The NPCs are in constant movement, which means that depending on how much time has elapsed, they will be at different locations. Rather than using the Crystarium System from the previous games, the protagonist's skills improve as she completes quests, some of which are optional and are either obtained at the Canvas of Prayer or given by NPCs. Every day at 6, Lightning is taken back to the Ark, where she gives Eradia, an energy bestowed by NPC quests, to the Yggdrasil tree to extend her allotted time. The enemies are visible on the World map, and whoever strikes before the battle starts first will deal damage to their opponent. Enemies will appear in larger number during night time. The battle use the Style-Change Active Time Battle System, an upgraded version of the previous game's Paradigm system. Lightning has access to different outfits that give her various abilities. The system is reminiscent of Final Fantasy X-2's Garment system. Such outfits are often inspired from other games, such as Final Fantasy VII and even from a cross-over scenario with Final Fantasy XIV: A Realm Reborn. Each garb has its own set of skills mapped to the controller buttons rather than in a list of commands.