Two men working on the docks close to London's Tower Bridge find the body of an unidentified man floating in the Thames. The police later identify the body to be that of a diamond courier from Holland. The police have to find his murderer, as well as the missing diamonds he was carrying.
| Actor | Role |
|---|---|
 Dermot WalshAlexander James | Alexander James |
 Sydney TaflerVictor Skinner | Victor Skinner |
 Mary GermaineRose Reid | Rose Reid |
| GGuy VerneySnow White | Snow White |
 Hugh MortonInspector Cathie | Inspector Cathie |
 James RaglanMr. Wynn | Mr. Wynn |
 Derek BlomfieldPhilip Reid | Philip Reid |
| NNicolas BentleyCollis | Collis |
 Arnold MarléOtto | Otto |
 John SerretDelbos | Delbos |
| AAnna TurnerHattie's Maid (uncredited) | Hattie's Maid (uncredited) |
| HHoward LangGaoler (uncredited) | Gaoler (uncredited) |