A neurosurgeon with a cheating wife takes an amnesiac into his home and conditions him to believe that the cheating wife is his own and to take the "appropriate" action.

Charles Bronson
as The Stranger

Anthony Perkins
as Laurence Jeffries

Jill Ireland
as Frances Jeffries

Henri Garcin
as Paul Damien

Agathe Natanson
as Lucy

André Penvern
as Intern

Denise Péronne
as Nurse

Carl Studer
as Fisherman (as Carl J. Studer)

Silvana Blasi
as Mrs. Evans

Adriano Magistretti
as Andrew