Lise Tanquerelle (Annie Girardot), police commissioner, is surprised to find that the motorcycle rider she has just hit with her car is none other than Antoine Lemercier (Philippe Noiret), a former classmate she hasn't seen for twenty years. This reunion gives rise to love at first sight, but Lise hides her profession from Antoine, who has become a Greek teacher and fiercely anti-police. Alongside this budding romance, Lise must investigate a series of bizarre murders: three deputies murdered in succession.