Yui was tormented by an obsessive feeling that someone was secretly watching her engage in lewd acts. Unbeknownst to her, the root of this distress was the fact that she had been repeatedly having sex with her husband's father in her daily life, far more often than she had realized. However, after being diagnosed at a psychiatric clinic, she was told by the doctor that this was a form of obsessive-compulsive disorder, and that her condition could improve by accepting the thoughts. Even after undergoing hypnosis therapy, her symptoms showed no improvement. During a follow-up consultation, she was given new advice: "The next time you feel that obsession, try inviting the one who's watching. That way, your psychological pattern will become clear." Believing these words, Yui returned home and began provocatively masturbating toward the direction where she sensed a gaze—only to encounter an unexpected turn of events.