Carroll Baker plays a dual role as translator Julie Harrison and her twin sister Mary. The serpentine plot begins as Julie tells her lawyer Dave Barton that Mary's life is being threatened in London while Julie herself is being stalked by a mysterious stranger in Amsterdam.
| Writing | Tito Carpi | Writer |
| Writing | Osvaldo Civirani | Writer |
| Camera | Walter Civirani | Director of Photography |
| Sound | Stelvio Cipriani | Original Music Composer |
| Directing | Osvaldo Civirani | Director |
