Medical researcher DR. KONG TUNG KIN (Bobby Au Yeung) is lonely and impolite. He's just a doctor that concentrates entirely on long-term drug research, until he met FONG SIU FONG (Tavia Yeung), who is naturally born allergic to chemicals. Unfortunately, a rule stated that DR. KONG cannot develop a relationship with his patients within 3 years. DR. KONG can only wait 3 years before he can confess his love to FONG.
3 years later, DR. KONG gets into a traffic accident and was on the verge of death, when he encountered the Devil TAI FUNG (Raymond Lam) who demanded for his life. However, because DR. KONG's wishes haven't been fulfilled, he begged for mercy from FUNG. He felt he never done anything that offended the Heavens, so he and FUNG came up with an agreement to prove that he's a good person. With FUNG's assistance, he was finally able to marry FONG. When everything seemed to be going smoothly, the most ugly side of human nature exposes. Was it all because of the Devil's trials or was it just the Devil inside that was causing all the troubles?