The story, adapted for the screen by the director and Caroline Eliacheff from Charlotte Armstrong's story, "The Chocolate Web," uses a brown throw crocheted by its central character, Mika (Isabelle Huppert), as its primary symbol. The throw, in the shape of a chocolate web, points to both the product made by the company Mika inherited from her father and that woman's perverse nature, which is "come into my web, said the spider to the fly." Mika has remarried a concert pianist, Andre Polonski (Jacques Dutronc) after the latter's second wife had died, having fallen asleep at the wheel. She becomes the stepmother of the aimless 18-year-old Guilaume Polonski (Rodolphe Pauly) who happens to be the exact age of a neighbor, Jeanne Pollet (Anna Mouglalis) whose mother, Louise (Brigitte Carillon), is a doctor working in a forensic lab. Upon suddenly hearing that there had been at least a temporary mixup in the hospital when she was born, Jeanne begins to wonder whether Andre might be her real daddy, particularly considering her resemblance to Andre's second wife, Lisbeth, and her ability with the piano. As the lively Jeanne plunges headlong into the Polonskis' Lausanne, Switzerland mansion, pumping Andre and later her own mother for clarification of her birth, she charms Andre into giving her lessons. Matthieu Chabrol's original score and the music of Liszt are insinuated throughout the film, which is photographed By Renato Berta creatively and without an American-style frenzy mostly within the pianist's home. Carefully and subtly we in the audience are asked to wonder about the hot chocolate made by the heiress. Did she add her husband's regular sleeping prescription, Rohypnol, to his second wife's drink to cause her to die at the wheel? What sort of potion is she mixing for others who get into her way, namely the 18-year-old woman who is causing her husband to feel young again? By extension, what might be in store for the aging board member Dufreigne (Michel Robin), who criticizes her marketing strategy at the company's meetings?

"Merci pour le chocolate" is a tone poem centered by Isabelle Huppert's riveting performance, a story set to music which, like Liszt's own tone poem is about shades and variations rather than, say, like a bold symphonic work with crashing themes like Beethoven's Fifth. Interestingly, the seventy-three-year old director had studied pharmacy, intending to move into his father's business, before he switched to film making which explains in part his use of a prescription drug and the forensic lab that employs two of his characters. Like Alfred Hitchcock, Chabrol uses characters who are detached, in this case almost narcoleptic, to further his vision of the turbulence that lies within them just as he did in two other "detached" works, "Les Cousin" and "Les Biches." "Merci pour le chocolat" is nicely nuanced, witty and humorous at times, building its tension without any concession to off-the-wall Hollywood-style melodrama.