Professor Marcilly is a famed brain specialist who, following in-depth and extended research work, is now able to perform brain transplant surgery. One day, he finds himself in the presence of a young car accident victim for whom the only hope of survival would be a brain transplant. Marcilly, who has a heart condition and is terminally ill, decides to become the "donor". The operation is a success. But who is actually the patient discharged from the hospital: a young fellow with the brain of a young man or an old man in the body of a young one?
as Franz Eckerman
as Le professeur Jean Marcilly
as Héléna
as Le docteur Robert Desagnac
as Marianne Marcilly
as Le docteur Catherine Ponson
as Costet
as Elisabeth Marcilly
as Ferrière
as Dino
