A young, beautiful prostitute named Sadie Thompson arrives on the South Pacific island of Pago Pago looking for honest work and falls for Timothy O'Hara, an American sailor who is unfazed by her unsavory past. However, Mr. Davidson, a missionary who arrived on the island at the same time, aims to "save" Sadie from her sinful life and petitions to have her separated from her beau and deported back to San Francisco.

The Allen spinsters adopt Bradley Nickerson, who grows up with Gussie Baker, the little girl next door. Fifteen years later he is first mate of the Thomas Doane, owned by Granny Baker. A plot to sink the ship is averted by Bradley and a sailor, but ultimately the ship is sabotaged.

Bob and Jim Whitely are twin brothers. Bob, an army veteran who suffered shell shock in the war, escapes from a sanitarium and holds up the Express train, for which Jim is mistakenly arrested. Jim soon escapes from jail in order to find his brother. However, his task is complicated by a crooked sheriff who pins a holdup and murder on him that the sheriff himself actually committed. To make matters worse, the murder victim was Tommy Wilkins, the brother of Jim's fiancee, who now thinks that Jim killed her brother.

Laura, a blind girl, has been cared for since infancy by Mike, Whitey, and Sal, three crooks who have kept her ignorant of her true surroundings. After an operation restores her sight, Laura is disillusioned and embittered by the sordidness of her environment. She falls under the evil influence of the gang's leader, Dennis Sullivan, who teaches her the art of safecracking. Just as Laura is about to perform her first job, her three benefactors are released from jail because of insufficient evidence and rush to the scene of the robbery to prevent Laura's corruption. The owner of the safe gives the four a ranch in reward for thwarting the robbery, and they all start a new life in the West.