Following a triple professional hit a U.S. agent, Paul Sherman, arrives in Amsterdam to investigate a heroin smuggling ring. He finds a city rife with drugs and a police force unable or unwilling to do much about it. With his incognito female fellow agent, Maggie, the American is soon stirring things up.
| Writing | Paul Wheeler | Screenplay |
| Writing | Alistair MacLean | Writer |
| Directing | Geoffrey Reeve | Director |
| Writing | Alistair MacLean | Novel |
| Writing | Don Sharp | Writer |
| Sound | Piero Piccioni | Original Music Composer |
| Directing | Don Sharp | Director |
| Production | Kurt Unger | Producer |
| Crew | Jack Hildyard | Cinematography |
| Editing | Bill Lenny | Editor |
| Production | Maude Spector | Casting |
| Art | Peter Mullins | Production Design |
| Art | Geoffrey Tozer | Art Direction |
| Directing | Terence Churcher | Assistant Director |
| Directing | Barry Langley | Assistant Director |
