In the chaos era caused by wars, people were living miserably except one small town which was unreasonably prosperous. Thus, many people were taking risks in search of the secret behind the prosperity. A girl from poor villages with her family’s testament and the fate of her village finally sneaked into the small town and discovered that the secret of the town’s prosperity was the King of Koi with trapped in the dungeon. After several efforts, she rescued the King of Koi and set foot on the road of escape.