Ha-yeong ("Viki") is a successful psychologist. One day she gets a secretive request from her sister Ha-joo (Lee Seung-chae). Apparently Ha-joo's husband Woo-seong (Kang Seong-pil) is refusing to have sex. Ha-yeong agrees to be their couple therapist but finds out that her brother-in-law actually has sexual desires for her and not her sister...