Those that enter the fog do not return.
This has been common knowledge in the countryside for close to two decades, now. Leave it to Nora N Dyr to test the limits on what a person should do when choosing a shortcut.
Upon entering, Nora discovers two things: One, the fog is full of monstrosities beyond comprehension. Two, there is a mad man, somehow, still alive in this hellscape. Against the odds, they are able to escape. Cursed with the knowledge of what lies within the fog (among a few other side effects), they are the only ones who can warn the nation of its impending danger