The Fighting Demon (1925)

John Drake, a college athlete, starts for South America, where he has been promised a good job on the strength of his knowledge of the construction of safes and vaults. Aboard ship, he falls in love with Dolores Darcy, the daughter of a leading Latin American banker. Arriving in South America, John discovers that he has been made the dupe of criminals, who want him to open the vault in Señor Darcy's bank. John refuses, and his passport and wallet are stolen. In desperation, he signs up to fight an exhibition bout with Dynamite Díaz, the South American boxing champion. Isaac Belding, the leader of the criminals, has John kidnapped, forcing him to open the Darcy vault. John locks the gang in the vault, telling the police of his actions on the way to the bout. John beats Díaz and then captures Pierce, the banker's secretary, who is in league with Belding. John becomes the hero of the town, and Dolores declares her love for him.