Into the Mirror (2003)

Wu Young-min was a police detective until a hostage situation went wrong. He fired at the hostage-taker's reflection in a mirror instead of the man himself, and his partner was killed. He quits and takes a job as head of security at Dreampia, a huge shopping mall owned by his uncle, which is being rebuilt after a deadly fire and is about to reopen.

Mall employees start dying. A woman is found with her throat cut in front of a toilet mirror, and a security technician also dies. The police call them suicides. Young-min does not believe it and starts his own investigation. The detective in charge, Ha Hyun-su, is an old colleague who blames Young-min for their friend's death and refuses to work with him.

In each case, the victim's reflection seems to act on its own. Young-min finds a link between the victims and the fire that closed the mall. He meets Lee Ji-hyun, a young woman with a history of mental illness, who tells him that her twin sister Jung-hyun died in the mall and is the one taking revenge.

The killings connect to the fire and to Jung-hyun's death inside the mall. Her spirit uses the mirrors as doorways back into the living world, punishing those tied to what happened to her. Reviewers note that the twins themselves reflect the film's theme of doubles: the living sister and the dead one stand in for each other, like a person and their reflection.

The film ends with a final twist about Young-min and his reflection. Fans read it in two main ways. One reading says the real Young-min died, and the man we see at the end is his reflection living on in the real world. The other says the opposite: Young-min has crossed over into the mirror world. The director leaves it open.

Either way, the ending ties back to the opening. Young-min's guilt began when he trusted a reflection instead of reality. At the end, the line between a man and his reflection is gone completely.