Prologue :Claude Chabrol is doing a very bad thing:phone-tapping .It might be dangerous,as Watergate testifies to.But let's be indulgent with him :telephone is a very useful invention ,and when it's (volontary)cut off,this mistake can have serious consequences.
A distraught girl(Zabou) comes to her daddy's (Michel Galabru)place :she has been beaten up by his violent husband ;he is an over - possessive father and can't accept that his dearest thing should be mistreated ,bullied ,by a crude brute.But the son-in-law is not prepared to accept it and he blackmails his wife :she'll have to come back home soon otherwise she will lose the custody of her only daughter....
This short is proof positive that a father-in-law can go on a pub- crawl with his sonny-in-law,but he must never ,in a month of Sundays ,try to kill him!
That's what Claude Chabrol tells us,perhaps wisely.