After serving together in the French Foreign Legion, a mercenary and a doctor leave the service and go their separate ways. Later, they are reunited and become involved with a caper involving millions in a high-security safe. The two men become locked in during a holiday weekend as they attempt to crack the safe's combination.

Alain Delon
as Dino Barran

Charles Bronson
as Franz Propp

Olga Georges-Picot
as Isabelle Moreau

Bernard Fresson
as Inspecteur Antoine Méloutis

Brigitte Fossey
as Dominique "Waterloo" Austerlitz

Ellen Bahl
as Martha

Michel Barcet
as L'inspecteur Muratti

Jean-Claude Ballard
as inspecteur de police

Marianna Falk
as Catherine

Jean-Paul Tribout
as inspecteur de police