On a planet far, far away from Earth, there reigns a kingdom overflowing with smiles. Princess Yuki is twelve years old and beginning to ride the roll…
Twelve-year-old Princess Yuki is starting to take on the responsibilities of leading her kingdom. But when the borderland knights Yuni and Lune are rude to her, her retainer Joshua challenges them to a battle in a simulator.
In order to hold back the advancing Imperial Army at the border, Grand Master Harold takes the royal flagship to the front lines. Joshua throws himself into his first combat sortie in order to protect Yuki's smile.
A soldier of the Imperial Army, Petty Officer Stella Shining always seems to keep her squad at arm's length. When she and her squad are deployed on a mission with their new commander, he wonders what lies behind her ever-present smile.
Two months have passed since the kingdom and the empire went to war, and the empire continues to advance. As Layla tries to support the despondent Yuki, she thinks back on the tragedy that started it all.
To break through a stalemate a stone's throw from the capital, the Buerger Squad embarks on a night mission. But when Lily runs into unexpected trouble, she ends up relaying her past to Commander Owens.
The Imperial Army approaches Hariant, the capital. The citizens are evacuated, but Yuki chooses to stay, hoping to find a way to prevent massive loss of life.
