Hell Froze Over

Some centuries after a cataclysmic event which ended with the world forever being plunged into an eternal winter, a lowly courier continues on with their routine, trudging through the snow to make ends meet. In other words, you're a mailman in the middle of a post-apocalypse. Sound familiar? Welcome, to my half-baked scenario that came to me in a dream (it did not, i'm just saying that for dramatic effect). This is my first time creating something 'original' and it probably shows. I am not exactly the greatest of writers and I definitely am not good at world building. Though, if enough people like this for some reason I might pump out a sequel with more lore or whatever. Probably.