Dr. Mack Lau (Tony Leung) is a cynical person on the surface, but he is actually very delicate and has a strong insight of the world. He despises the injustice of the health care system and runs his own clinic in a red-light district. Indulged in medical science, Mack possess superior medical skills and is passionate in treating underprivileged citizens. Among his patients include a brave policeman, Chiu, his neighbor prostitutes and so on. Aside from healing his patient's wounds, Mack is also willing to listen to their thoughts and become their friend. However, Mack was later framed by his old friend and medical classmate, Roger Law (Alex To), and must face the crisis of his doctor's license being revoked.