Arang and the Magistrate is based on famous folklore, as all
ghost stories are: During the Joseon era in the city of Milyang,
Arang was the pure, beautiful, good-hearted daughter of a
magistrate. (Magistrates figure into a LOT of
Korean folklore, as they are the local men of power, and often
depicted as abusing said power or meeting some untimely demise.)
She grew up without a mother, and was raised by a wicked caretaker
who conspired to have her be raped and ruined by a servant. He
attacked and she resisted, so he stabbed and killed her, and left
her body to rot in the woods.
Her father the magistrate just believed that she eloped with a
man (dishonorably, of course) and so resigned his position swathed
in shame. Thus the legend goes that every time a new magistrate
comes to Milyang to fill the position, Arang’s vengeful ghost shows
up to tell him her story and he flees in terror.
But one day a new magistrate comes to town — a young man by the
name of Lee Sang-sa. Arang appears to him like every other
magistrate before him, but this man doesn’t flee, and instead
sympathizes with Arang, and promises to find her killer and avenge
her death.