Lucky Sky Diamond (1989)

At the clinic where her boyfriend Katayama, a young genius doctor, is the director, Yoko, a young girl who continues to suffer from eerie nightmares every day, is not getting better despite the care of her sister Sakurako and Katayama's treatment. Sakurako, the sister, is suspicious of Yoko's condition and confronts Katayama, who tells her that she suffers from a serious mental disorder and that the only way to cure it is to have brain surgery. Yoko, despite being persuaded by her sister and Katayama, agrees to the surgery, although she is skeptical...