When night falls, we find peace in the knowledge that daytime will return soon, and vice versa. But what if the world was split: daytime and night are two different, coexistent worlds, each with it's own laws and rules. At dawn and sunset, our soul switches to inhabit our other being, our 'twin'.
A typical iron ore mine, the Irongate was closed some years ago and the entrance was closed off with a heavy gate of oak and thick iron bands, the Irongate. The mine itself was abandoned because it was a breeding ground for dire rats and many of the miners suffered from giant rodent bites as well as diseases from said bites. The mines are haunted by the ghosts of the men who died in dire rat swarms, adding to the mine's unpleasant character.