The story is set in a world with a continent split down the middle by a mountain range and a vast river. The eastern side is known as Roxche, and the western side is Sou Beil. The two sides have been at war for the past 130 years, though an armistice has been in effect for the past ten years. Wil, a young man from Roxche who enjoys reading books and has a photographic memory, is spending a leisurely summer vacation at his school's dormitory when his old friend Allison, a young girl his age who is now an Air Force pilot, arrives in a biplane to greet him after not seeing him for six months. The two take a drive together on Wil's motorcycle from school and run across an old man waiting on a bridge who is well-known in the area for telling false stories. They give him a ride to his home, and while there he tells them a story he claims to be true: that there is a treasure in the western region Sou Beil which could end the conflict between the warring regions. Before he can tell them more, a man who claims to be from the town hall takes the old man away, though Wil quickly notices that the man was most likely lying. Allison and Wil chase after them and find that the old man was taken away in a large plane. Allison and Wil steal a plane in order to find out where the old man was taken.

While chasing the plane, Allison and Wil get attacked by a fighter plane and while getting away got tangled on some power lines, ultimately causing their plane to crash. As the sun is rising, Allison sees a fawn and approaches it, only to anger the fawn's mother which goes to attack Allison, but Wil gets in the way as the deer hooves his head, making him pass out. Allison carries him most of the rest of the day until they find a cottage with a single old woman who treats Wil injuries and listens to Allison's reasons for coming over to the western region. Via Allison's and Wil's sleep talking, the woman discovers that they knew and grew up with an old woman named Moot who had defected to Roxche to run an orphanage; she was known henceforth as a traitor in Sou Beil. After hearing the hardships they have been through, the woman's opinion of them and people in general from Roxche changes. She gives them her now-dead husband's and son's military uniforms to aide in their rescue of the abducted old man.

Allison and Wil are now married and living together in an apartment in the city. Allison's father comes to Wil and asks him to become a member of the Sou Beil intelligence agency that he himself is a member of, but Wil would have to create a new life and throw away his old one. After thinking for a long time, he informs Allison of his plans and she accepts that he has to do what he must do. Before he left, Wil got Allison pregnant, though he learns of this after he has left. Fifteen years pass and Allison is living in the same apartment with her daughter Lilliane, or Lillia for short. This day, Allison has a date with a man named Travas, though he is in fact Wil albeit with a different hair color.