In the Buée City, it is separated into three-the fire zone, ice zone, and midway zone. No one knows what life is like outside the city. it's surrounded by a technical barrier that stops anyone from coming in or out. People are segregated and must have zero contact with each other. one half has Fire abilities, and the other has Ice-there is no in-between. A girl named Chaeie and a boy named Heoden meet one day by accident and decide to end this segregation.