Tsubame sees freedom in his eyes, like a swallow escaping its cage. In the East Asian Desert, at #13 Salvage Camp, Tsubame works as a metal scrap collector, trying to earn enough money to travel alone, like a free swallow. But one day, a girl is found buried in the sand with a keyhole on her wrist—the symbol of a Kagijin, someone who possesses demonic powers capable of withstanding an army. The empire that kept her as a slave arrives to retrieve her, but Tsubame refuses to hand her over and promises to free her. How will he do it? And what significance does the key hanging around his monkey's neck hold? Read and find out!