"This tale of intrigue finds Valentina Cortese involved in an assassination plot. She helps the police apprehend the conspirators after an innocent bystander is accidentally killed."
Valentina Cortese
as Maria Brentano / Brent / Lena Collins
Serge Reggiani
as Louis Balan
Audrey Hepburn
as Nora Brentano
Megs Jenkins
as Penny
Irene Worth
as Miss Jackson
Reginald Tate
as Inspector Eliot
Charles Goldner
as Anselmo
Angela Fouldes
as Nora Brentano as a child
Simone Silva
as Undetermined (Minor Role - Paris Sequence) (uncredited)
Norman Williams
as Sergeant Newcome
Michael Shepley
as Manager of the British Pavilion
Athene Seyler
as Mrs. Reginald Kellick
Sydney Tafler
as Syd Burnett
Geoffrey Hibbert
as Steenie
John Ruddock
as Daly
Michael Allan
as Rodd
John Field
as Fedor Luki
Hugo Schuster
as General Galbern
Lionel Harris
as Frack
Rollo Gamble
as Bentley
John Penrose
as Bill
John Chandos
as John
Michael Ripper
as Charlie
Louis Mansi
as Member of Paris Committee
John Gabriel
Olga Landiak
Frederick Schiller
as Galbern's Bodyguard
Phaedros Antonio
Gaston Richer
as Queval
Derek Elphinstone
as Plain Clothes Man
Edward Evans
Jack McNaughton
as Postman
Ingeborg von Kusserow
as Shoe Shop Girl
Bob Monkhouse
as Hairdresser
Helen Ford
as Scarf Woman
Ann Lancaster
as Manicurist
Grace Draper
as Floozie
Bertram Shuttleworth
as Little Man
Pamela Harrington
as Waitress
John Allen
as The Valet
Bay White
as Nursing Sister
Joe Linnane
as Irish Police Inspector
Sam Kydd
as Irish Police Sergeant
Thorold Dickinson
Story
Director
Screenplay
Joyce Cary
Wolfgang Wilhelm
Sidney Cole
Producer
Norman Priggen
Assistant Director
Chic Waterson
Camera Operator
Ernest Taylor
Makeup Artist
Roberto Gerhard
Music
Ernest Irving
Conductor
Gordon Dines
Director of Photography
Anthony Mendleson
Costume Designer
Arthur Bradburn
Sound Recordist
William Kellner
Art Direction
Harry Wilton
Barbara Barnard
Hairstylist
Christianna Brand
Additional Dialogue
Peter Tanner
Editor
Ralph D. Hogg
Unit Production Manager
Hal Mason
Production Supervisor
Stephen Dalby
Sound Supervisor
Andrée Howard
Choreographer
Phyllis Crocker
Continuity
Sydney Pearson
Special Effects
Roy Gough
Still Photographer