Dumézil’s trifunctional theory applied to the only grail plot in Chrétien de Troyes’ Conte du Graal proves to be neither faithful nor worthy of credit. Philological, historical, cultural, cognitive and narratological arguments raise critical objections and question its artificial character. In fact, the incidental episode of the grail functions as a narrative drawer in a plot belonging to the global tale ATU 910B (Good precepts) relating to the part of the work regarding Perceval.