This is the story of a British doctor named Walter Fane (Edward Norton) who loves a young girl named Kitty (Naomi Watts). She is only interested in parties and pleasure but agrees to marry him. They travel to Shaghai where Walter works in a laboratory researching infectious diseases. Kitty begins an affair with a British official (Liev Schreiber). When Walter discovers this, he forces Kitty to accompany him to a rural area where there is a cholera epidemic. The couple are faced with great dangers both from the epidemic and from discontent among the local population but eventually come to respect and love each other.