Plot summary
Kang Yu-jin, a wealthy biology professor doing a butterfly field study, takes in a new housemaid; the young woman, Mi-ok, is the daughter of a shaman priestess who recently died in a house fire. At first, Yu-jin and his wife, Seon-hee, welcome Mi-ok into their home, but Seon-hee begins to have misgivings when she sees a strange wooden doll that the maid has brought with her. Having suffered from nightmares about exactly the same doll, Seon-hee becomes increasingly suspicious and paranoid that Mi-ok is trying to kill her and usurp her household. In a sudden fit of madness, Seon-hee causes Mi-ok to fall to her death. From then on, Seon-hee is tormented horribly by visions of the doll attacking her and it starts to take a great toll on her sanity. Is it actually happening or just all in the girl's mind?
Credits
Adapted from Wikipedia contributors, Suddenly at Midnight. Section headings and formatting adjusted.