Milf mother Sayuri Kuroyama had raised her cheerful son, but one day he suddenly became a shut-in, leaving her utterly distressed. Unaware that her son had become obsessed after seeing her jet-black armpit hair, she remains ignorant of the growing fixation. This obsession doesn't stop with her son—it begins to affect his homeroom teacher, who comes to counsel her. Furthermore, after the teacher accidentally sees her completely shaved pussy, his mind is equally disturbed. As tensions rise, her son's emotions grow stronger each day—until he can no longer hold back…!