In 1947 during the Chinese Civil War, Catholic priest Father O'Shea (Humphrey Bogart) arrives at a remote Chinese mission, after nearly drowning and losing his possessions on the way. There he meets Dr. David Sigman (E.G. Marshall), his wife, Beryl (Agnes Moorehead), and nurse Anne Scott (Gene Tierney). Sigman tells O'Shea he believes the mission should be closed because of the local population's fear of warlord Mieh Yang (Lee J. Cobb). O'Shea soon gains the respect of the parishioners by preaching to them in Chinese. Problems arise when O'Shea strikes a stranger who spits at him and Anne becomes attracted to him. When O'Shea tells Anne that the mission should be closed, she reveals that she came to China after her pilot husband crashed and hoped he would be found alive, but now knows he is dead and is dedicated to helping the villagers. O'Shea realizes her attraction and after consulting Beryl, he seeks advice from Protestant Reverend Martin (Robert Burton). He startingly reveals to Martin that he is actually Jim Carmody, a pilot who crashed and was forced to work for Yang. After the man who spat on Carmody murdered the real O'Shea, Carmody took his place to escape. Unfortunately, Yang soon arrives with his army and threatens the villages with intention of forcing Carmody to reveal himself and return to Yang's service. Determined to end the threat, Carmody faces Yang alone.
—Patrick Depew