A drama of the river underworld

Merchant sailor Dan MacDonald has a lucrative sideline in smuggling black market goods ashore. While docked in London, MacDonald and his best friend, Johnny Lambert, get mixed up with a gang of ruthless jewel thieves, who hire MacDonald to smuggle their loot out of the country. Complications arise when Johnny falls for a charming but pernicious young woman named Pat, and is falsely charged with murder.