A dozen elegant people are gathered in a writer's desirable mansion. In the grand tradition of Agatha Christie, they all have something to hide.They begin a cruel game of truth, a game where you're not supposed to tell lies. As the questions become more and more intimate and precise, the tempers rise, while outside the storm is raging. Enter a hateful person (played by Paul Meurisse, the nasty headmaster in "Les Diaboliques") who seems to know a lot about them. Someone is murdered. Whodunit?

Robert Hossein
as L'inspecteur de police

Françoise Prévost
as Guylaine de Fleury

Paul Meurisse
as Portrant

Jean Servais
as Jean-François Vérate

Nadia Gray
as Solange Vérate

Jean-Louis Trintignant
as Guy de Fleury

Perrette Pradier
as Florence Geder

Jeanne Valérie
as Françoise Bribant

Jacques Dacqmine
as Guillaume Geder

Tiny Yong
as La fille eurasienne