British diamond smugglers use the radiowoman (Phyllis Kirk) from a freighter docked on the Thames to unwittingly "mule" their swag, hidden in cigarettes, past customs, not knowing that she has befriended an Inspector for the Thames River Patrol.

• Victor Hanbury Productions
• John Bentley
• Phyllis Kirk
• Leonard White
• Glyn Houston
• Patrick Jordan
• Harold Ayer
• David Hurst
• Charles Lloyd Pack