We all experience birth, old age, sickness and death. Yet have you ever wondered who determines the time of our death? Respected pharmaceutical doctor KONG TUNG-KIN (Au Yeung Chun Wah) starts up his own clinic after a drug trial incident. One day, he is approached by TOI FUNG (Raymond Lam), who claims to be Satan, for a patient’s life. Refusing to do so, he suggests handing over his own. His reaction takes FUNG by surprise. With a view to getting to know more about human being, FUNG interferes with KIN’s life, including his family and career. In addition, he runs after FONG SIU-FONG (Tavia Yeung), a nurse KIN has been secretly in love with. Later, KIN sells his soul to FUNG for money and fame. As time goes by, he starts to become a totally different person, losing his kindness without himself knowing it.