In a small French town, a bitter, demanding invalid mother (Audran) and her dutiful, oppressed son (Belvaux) are pressured to sell their land for a shady development deal, and decide to fight back. When one of the scheme's sponsors ends up dead in a most unusual way, the skilled and determined Inspector Lavardin (Poiret) arrives to uncover and clean up the mystery.

More aptly titled "Poulet Au Vinaigre" ("Chicken With Vinegar") in France, this quintessential Chabrol whodunit is indeed a pungently sour portrayal of the deadly intrigues that can hatch in seemingly close-knit placid communities. This "Cop" is extremely well-played, with Chabrol's former wife Audran extremely effective playing a harridan, and Poiret a stand-out as Lavardin a savvy professional who can be courteous one minute then brutal the next. This under-exposed Chabrol puzzler is a must for mystery fans.