Minato (Maki Horikita) was abandoned by her parents at a young age and forced to live with her senile grandmother, a situation which traumatized her deeply. To pass the time she starts corresponding with a pen-pal named Night, a boy of about her age. Through her letters to Night she chronicles the daily goings-on of her life, and eventually even admits to him that she’s falling in love with a boy she’s met named Sho (Takuya Ishida). One day she notices Sho is apprehensive around her and acting oddly. She suspects Night may be the cause but when she arranges to meet with him in person and sort this out he never shows up. What she isn’t consciously aware of, however, is that Night is actually her overprotective split personality and bullies Sho to drive him away from the more trusting Minato.