In a distant kingdom on a planet far from Earth, Princess Yuuki, at the tender age of 12, navigates the complexities of growing up with a mix of tears, laughter, and moments of excitement in the royal palace. Alongside her devoted vassals like Reira, Izana, Harold, and her childhood friend Joshua, Yuuki's days are vibrant and full of life. Meanwhile, Stella, a 17-year-old skilled soldier, maintains a reserved demeanor but always wears a smile, believing it to be crucial for existence. This tale unfolds the lives of two young girls hailing from separate planets, intertwined by fate.