A world split into four regions, in which none know of each other. To siblings Yim Younghee and Yim Youngjun, Winter was their entire world, and Spring, Summer, and Autumn were simple myths—fairy tales. They don’t exist. They were born into an eternal winter, and were never to leave.

But when they wander a little too far away from home, they find a corpse and a single flower lying in the thick blanket of snow. In a frenzy of events, they find themselves in a new, uncomfortably warm land, where they begin to discover the terrible truths about their world.