The film stars Edmund Gwenn, who plays a chemist, whose son Lawrence (played by Barry MacKay) is attacked on a train. He appears to have shot the man.
| Actor | Role |
|---|---|
 Edmund GwennDavid Lawrence | David Lawrence |
 Barry MacKayJim Lawrence | Jim Lawrence |
 Aileen MarsonMary Willett | Mary Willett |
 D.A. Clarke-SmithStranger | Stranger |
 Viola LyelMrs. Willett | Mrs. Willett |
 Wally PatchSergeant | Sergeant |
 John TurnbullInspector Goodall | Inspector Goodall |
 Barbara EverestMrs. Lawrence | Mrs. Lawrence |
| BBeatrice MarsdenMrs. Smith | Mrs. Smith |
| PPhilip HewlandMinor Role | Minor Role |
| BBarry O'NeillMinor Role | Minor Role |