House of Evil Spirits (1980)

A suspense work starring Junko Natsu. One night, Saiko Ogata, a popular female DJ on a late-night radio music program, discovers a strange letter among a pile of postcards. It was a letter written in the style of a 5 or 6-year-old child, beginning with, "Mom, I am in a dark and cold world right now." Saiko is shocked. That letter was a letter from her own child, whose father was Kazuo Yamazaki, whom Saiko had fallen in love with six years ago when they were trainees at a certain theater company, and who had sprouted in Saiko's womb but passed away without being born...