Before her father-in-law collapsed from a cerebral infarction, he raped Mai, who was left behind by her husband on a long business trip overseas, and collapsed during their sex. Then, on the way back to Japan, her husband also died of the same cerebral infarction. The in-laws gathered at the wake and attacked Mai. The sister-in-law and mother-in-law were also involved, and the incestuous rape party began.