Prier and her brother Culotte are novices with the demon-hunting organization, La Pucelle. They've just passed their final exams and are ready to do real work fighting demons and zombies, but quickly find themselves embroiled in a series of plots orchestrated by a rival church with dark intentions. The gameplay is played on a tactical map, as teams up to six characters work to clear boards of enemies and dark energy. The unique "purify" command allows players to recruit monsters to their team and execute complex "miracle" energy attacks.

The game was ported to the PlayStation Portable in Japan on November 26, 2009 as La Pucelle Ragnarok.

La Pucelle takes place in a kingdom named Paprica. The story centers on a small church called the Church of the Holy Maiden, in the city of Pot a Feu. In addition to the normal roles and duties of a Church, they also have a group of trained Demon Hunters called La Pucelle. Two of La Pucelle's newest members are Prier, a sixteen-year-old girl, and her twelve-year-old brother Culotte.

It is said that the Dark Prince, favored servant of the fallen angel Calamity, will rise to scourge the land. But legend tells that when the Prince arises, a warrior known as the Maiden of Light will challenge him and restore the balance of Light and Dark. Prier hopes to be the Maiden of Light.

The game's story is broken up into chapters. Each chapter has a number of endings, depending on the information La Pucelle discovers before reaching the chapter's end.