"Your sister." The words that came from the woman who would become his wife were resolute. *** Therapist Hye-won massages a mysterious client in a dark room every dawn. The client has never shown their face and has contracted Hye-won as their personal masseuse under the condition that the lights must never be turned on. She is the top manager of the massive building where the premium therapist shop employing Hye-won is located, and is referred to as 'God' by the shop's owner. One day, this 'God'-like client tells Hye-won that they are about to get married and asks her to become their personal therapist. Meanwhile, her doctor brother Hee-jun contacts her, saying he has a woman to introduce. However, on the day of the appointment, Hee-jun cannot come due to an emergency patient, and only the woman promised to marry Hee-jun comes to meet Hye-won. But this woman seems to show a strange interest only in Hye-won, putting Hee-jun aside...