In the past, there was a goddess whom extended a helping hand to a world that was about to perish. That goddess, along with the four knights who served her, healed the ruined land using "Grace", a power that rejuvenates worn down life forces, and saved the world.
Ever since then, because the goddess' consciousness went into a slumber, she was to be succeeded by someone who will become a representation of her divine spirit, known as a "Reine", and four human knights that were chosen by the world. As the world continued to enjoy the goddess' favour, it continued to develop and advance.
However, at a certain point, even after coming into the world for generations, a Reine was not born. As a result, the supplies of Grace stagnated, and the world was once again threatened to be consumed by darkness.
But finally, the Reine of the next era, "Violette" was born. Adhering to the customs, she selected four men to become the queen's knights. However, the hearts of those men rejected to bond with the Reine, due to the Reine's long absence.
In order to supply the world with Grace, the co-operation of the knights is essential.
To obtain the trust and loyalty of the knights, Violette begins to take action...
[Translation of the official website's summary.]