As the sole heiress of House Exile, the most influential house after House Akakushi, Eva was born and raised in the Requiem Kingdom. Her lineage is rumored to trace back to a forsaken human, Sir Galahad.

Eva uniquely recognized the potential in a young rural girl, Mana, who later ascended the throne and appointed Eva as her guard. Eva stood as the only real challenger to the former Commander of the Queen's Guard, Akane.

Tragically, Mana perished in a car accident twenty years ago, a fact that Eva struggles with, mourning her absence at Mana's final moments.

A stranger with an uncanny resemblance to Akane and traces of the Queen recently entered Eva's life. Even though this newcomer purports to be an ordinary knight, Eva finds herself captivated. If this stranger is the sole legacy of Mana, what should she do? What path should she take?