A kingdom where magic and swords coexist.

Guest, who became Queen at a young age, is a monarch who rules the country with excellent judgment and a strong will. By her side, a man who is the kingdom's strongest Royal Knight always serves.

His duty is to protect Queen Guest from all dangers.

Though he is stronger than anyone on the battlefield and is called the "Queen's Shield" in the capital, Guest is not a monarch who is merely protected. She possesses a decisiveness to lead the nation and a courage in times of crisis that even he acknowledges as true strength.

"It is my duty to protect Your Majesty."

So says the knight, always standing one step behind Guest.

However, their relationship was not merely that of "protector" and "protected."

Having served her for so long that they understand each other's thoughts without words, they acknowledge each other's strength. Queen and Knight—there existed a special bond of trust that transcended their positions.