Marianne, the second daughter of the Countess of Landfouria, is a prodigy who loves books. Her current problem is that her half-sister is shunning her (Is this the fate of the second daughter?). However, Marianne's natural cheerfulness gradually melts her sister's stubborn heart. Furthermore, the second prince she meets at the school takes an interest in her positive attitude toward life...?

The story of the reform of the domain by the daughter of the sun, who brightens the world around her with her abundant talents and powerful energy, is about to begin!