Shinya Tsukamoto, the cult director of the cyberpunk Tetsuo series, presents an unnerving film about mental instability. Kotoko (singer-songwriter Cocco), a young single mother, lives alone with her baby son. Suffering from an unknown illness that makes her see double - especially people - and not knowing which version of the person is real, it severely impacts her day-to-day life, often leading to her to lash out violently. As her situation worsens and she becomes a liability, her son is taken from her and put in the care of her sister. Kotoko is left alone with her own thoughts - and for a person with an already broken mind that is a very scary place indeed.
I found this movie a bit incomprehensible and I'm a fan of Asian Horror films. I would call it more a portrait in abnormal psychology more than a horror film. Kotoko is an extremely disturbed young mother who is inexplicably courted by a popular novelist. First, one wonders how such a woman would be allowed to wander the streets, let alone have a child. Then, one wonders how anyone could be intrigued enough to want to have a relationship with her. The fact that she sings well is incidental to the movie and adds nothing to the plot. If you want to see great horror, rent Old Boy instead.