Doctor Knock is a former thug who has become a doctor and arrives in the small village of Saint-Maurice to make his fortune according to a particular method. It will make the villagers believe that they are not as healthy as they might think. It is thus that he will find in each one an imaginary symptom, or not, and thus will be able to exercise his profession lucratively. Under his seductive looks and after gaining the confidence of the village, Knock is on the verge of achieving his ends. But his past catches up with him and an old acquaintance disrupts the doctor's plans.
When Arthur decided to become a policeman it was most definitely not so that he would be put on the trail of a group of ultra-left wing artists, the Black Fist Collective. No, his real motivation was so that he could trace his father, Public Enemy Number One, La Malice. But, alas, it is Chief Inspector Moulinette who sets the rules, assisted by his faithful lieutenant Gégé. Arthur has no choice but to infiltrate the troublesome Collective, by posing as an actor...