"Charles Van Horn, son of rich and powerful Théo Van Horn, calls upon his former teacher Paul Régis to help him solve the mystery of his recurring bouts of amnesia."
Anthony Perkins
as Charles Van Horn
Michel Piccoli
as Paul Regis
Marlène Jobert
as Hélène Van Horn
Orson Welles
as Théo Van Horn
Guido Alberti
as Ludovic Van Horn
Ermanno Casanova
as One-Eyed Old Man
Mathilde Ceccarelli
as Receptionist
Eric Frisdal
as Charles enfant
Aline Mantovani
as Hélène enfant
Corinne Koeningswarter
Tsilla Chelton
as Mère Théo
Giovanni Sciuto
as Prêteur
Vittorio Sanipoli
as Commissaire
Fabienne Gaugloff
as Petite fille du train
Silvana Blasi
as La réceptionniste de l'hôtel d'Alsace (uncredited)
André Génovès
Producer
Claude Chabrol
Director
Frederic Dannay
Writer
Manfred Lee
Paul Gégauff
Ellery Queen
Original Story
Jean Rabier
Director of Photography
Jacques Gaillard
Editor
Eugene Archer
Screenplay
Paul Gardner
Pierre Jansen
Music
Karl Lagerfeld
Costume Design
Guy Maugin
Set Decoration
Guy Littaye
Production Design
Jacky Bouban
Makeup Artist
François-Xavier Leclerc
Jacky Reynal
Alaine Scemama
Hairstylist