The story is set in a world in which there are two groups in apparent opposition: the Luminous church, and the witches.
During the course of the story, the player controls a party made up of orphans who have been raised by the Luminous church. They are called the Garden Children, and are tasked with the condemnation of witches. However, soon after the beginning of the story, it becomes evident that things are not as clear-cut as they initially seem.
Structurally, the party moves from area to area, and the plot advances as the player progresses through battles. Equipment may be powered up through the use of a vitae forging system. Also, relationships with characters may be strengthened during post-fight "intermissions," leading to some bonuses in future battles.