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'.
The villages around the capital have a strange new disease cropping up. Spread by a fungus (much like ergot poisoning), it causes its victims to be very sensitive to sunlight. Hundreds of peasants are hiding from the sun, only coming out in the darkness to labor in the fields. Unfortunately, rumor makes their behavior sound more sinister and secretive than it really is.