Police inspector Diamant is investigating the murder of two black
girls. They were both sacrificed, hung, their faces covered with
a ceremonial mask from Mali. The suspects include Daniel Cisse
and his father, who came from Mali twenty years previously.
Diamant enlists the help of the ethno-psychiatrist Professor Taiev, a
specialist in psychiatric disorders in immigrants.
In the 1940s, the shadowy, skewed visual style of 1920s German expressionism was taken up by directors of American thrillers and psychological dramas, creating that distinctive film noir look.
It was American film noir and pulp fiction that kick-started the craze for thrillers in 1950s France and made it one of the most popular and enduring genres.