Humble stamp dealer Otto Becker has little to do with international politics, so when he receives a surprise visit from his estranged twin brother and Nazi spy, Baron Hugo von Detner, his world is thrown into turmoil. Threatening Becker with deportation, Hugo forces him to use his shop as a front for espionage.
| Camera | Harry Stradling Sr. | Director of Photography |
| Directing | Jules Dassin | Director |
| Editing | Frank E. Hull | Editor |
| Production | Irving Asher | Producer |
| Art | Cedric Gibbons | Art Direction |
| Costume & Make-Up | Howard Shoup | Costume Design |
| Sound | Lennie Hayton | Original Music Composer |
| Writing | Paul Gangelin | Screenplay |
| Writing | John Meehan Jr. | Screenplay |
| Art | Edwin B. Willis | Set Decoration |
| Costume & Make-Up | Jack Dawn | Makeup Artist |
| Costume & Make-Up | Sydney Guilaroff | Hairstylist |
| Sound | Douglas Shearer | Sound Director |
| Art | Stan Rogers | Art Direction |
| Writing | Lothar Mendes | Story |
| Sound | Daniele Amfitheatrof | Music |
| Sound | Bronislau Kaper | Music |
| Sound | Sol Kaplan | Music |
| Sound | David Snell | Music |
| Crew | Duke York | Stunts |
| Sound | Wally Heglin | Orchestrator |
| Sound | Joseph Nussbaum | Orchestrator |
| Sound | Leonid Raab | Orchestrator |
