Mr Jo, nicknamed "the man with the Buick", is the darling of the small town of Honfleur. But he is in fact a trafficker with a bad reputation who would like to forget about his past, now limiting himself to smuggling rubies under the cover of a charitable organization which offers underprivileged children holidays in Switzerland. However, Mr. Jo is in love with a pretty widow and, in order to marry her, he is willing to get involved in a hold-up again. And "the man with the Buick", who seemed so honorable, will surprise the inhabitants of Honfleur when Inspector Menard reveals his secret activities.

A Paris flea market vendor is transformed into a vigilante after his fiancée is murdered by three vicious thugs on a commuter train. As the revenge-minded young man tracks the killers, a veteran police inspector leads a parallel investigation.

Retrato de la alta sociedad francesa. Leda, el ligue del señor Marcoux, es asesinada. Su familia prefiere dejar que la policía inculpe a un inocente, que no pertenece al círculo familiar, pero el prometido de la hija de Marcoux no está de acuerdo.

It is based on upon the memoir Mémoires d'un agent secret de la France libre et La Ligne de démarcation by Gilbert Renault under his pseudonym Colonel Rémy. A small village in the Jura is split by the river Loue which creates the line of demarcation between Nazi occupied France and freedom. A French officer, Pierre, is released by the Nazi soldiers to find his chateau converted into a German command centre. Whilst he is obliged to co-operate with the enemy, his wife Mary supports the resistance movement and is willing to risk her life for it. The Nazis step up their activity against the resistance, insisting that any who attempt to cross the line of demarcation will be shot. When his wife is arrested, Pierre decides to switch his allegiance.

1970 film by Jacques Deray