Long ago, a goddess and her four knights used the power called Grace to heal a dying world. The goddess has since gone into a deep slumber. In her absence, the world has been maintained through successive Reine—human representatives of the goddess's divine spirit—each paired with four chosen knights. After an unusually long gap with no Reine born, the Grace has stopped flowing and the world is again threatened by darkness. Finally, a new Reine named Violette has emerged. She has selected four knights as custom demands—but the knights' hearts resist the bond, damaged by the long absence. Without their cooperation, Grace cannot be restored. Violette must earn the trust that the intervening years have eroded.