Stop at Nothing (1924)

Burley Walters and 'Shadow' Brice, rival crook leaders are after the Denman diamonds. 'Shadow' wins the confidence of Daphne Denman, but Walters beats him to it and gets the diamonds as they are being transported on a San Francisco ferry boat. After a furious fight 'Shadow' wrests the gems from Walters and then reveals himself to the girl as a secret service man.