In this classic of French suspense, the cruel and abusive headmaster of a boarding school, Michel Delassalle, becomes the target of a murder plot hatched by an unlikely duo — his meek wife and the mistress he brazenly flaunts. The women, brought together by their mutual hatred for the man, pull off the crime but become increasingly unhinged by a series of odd occurrences after Delassalle’s corpse mysteriously disappears.

Passengers on a ship traveling from Mexico to Europe in the 1930s represent society at large in that era. The crew is German, including the ship’s Dr. Schumann, who falls in love with one of the passengers, La Condesa. A young American woman, Jenny, is traveling with the man she loves, David. Jenny is fascinated and puzzled by just who some of the other passengers are.

Charles Dobbs is a British secret agent investigating the apparent suicide of Foreign Office official Samuel Fennan. Dobbs suspects that Fennan’s wife, Elsa, a survivor of a Nazi Germany extermination camp, might have some clues, but other officials want Dobbs to drop the case. So Dobbs hires a retiring inspector, Mendel, to quietly make inquiries. Dobbs isn’t at all sure as there are a number of anomalies that simply can’t be explained away. Dobbs is also having trouble at home with his errant wife, whom he very much loves, having frequent affairs. He’s also pleased to see an old friend, Dieter Frey, who he recruited after the war. With the assistance of a colleague and a retired policeman, Dobbs tries to piece together just who is the spy and who in fact assassinated Fennan.

Betrayed by an informant, Philippe Gerbier finds himself trapped in a torturous Nazi prison camp. Though Gerbier escapes to rejoin the Resistance in occupied Marseilles, France, and exacts his revenge on the informant, he must continue a quiet, seemingly endless battle against the Nazis in an atmosphere of tension, paranoia and distrust.