Marseilles, 1919. Georges Sarret is a distinguished and respected lawyer, recently honoured for his services in the First World War. He takes as his lover Philomène Schmidt, a young German woman, who has just lost her job and home. To enable Philomène to remain in France, Georges finds her a husband – who dies conveniently of natural causes a month after the wedding. Georges repeats the trick with Philomène's sister, Catherine – marrying her off to an old man who dies suddenly so that the scheming trio can profit from his life insurance. When an accomplice in the scheme, Marcel Chambon, threatens to blackmail them, Georges and his two lovers have no option but to kill him and his mistress...

Three sideshow performers form a conspiracy known as "The Unholy Three" - a ventriloquist, midget, and strongman working together to commit a series of robberies.