On a planet far from Earth, there is a kingdom full of smiling faces. Princess Yūki is 12 years old, and about to enter a sensitive age in a person's life. Everyday, she cries, laughs, and sometimes, her heart throbs with excitement. All the while, she lives merrily in the royal palace. Filling her days with color are her loyal vassals: her tutor Reira, Izana who assists in political affairs, the leader of the chivalry Harold and then, there is her childhood friend and aide Joshua. Stella is 17 years old and a capable, reserved soldier. However, she is always smiling for smiling is essential to living.