The role of the doctor in a factory. The investigations he makes to discover the origin of ailments which attack the workers in a large chemical factory.
Resnais conceives the cutting, assures the preparation and the editing, but has to delegate the shooting to his former assistant André Heinrich.
" Resnais suggests (except precise notes), brings people to do exactly what he wishes without imposing anything on them . They said that The Mystery was the least good short film by Resnais. As far as the movie is a little of me, I am sure that it is my best short film. "
André Heinrich, " The Avant-Scène cinema ", in July-September, 1966.