The Baroness de Courtebise presides over an association of mothers-in-law with grievances against their sons-in-law. Armed with her prerogatives, she forbids the marriage of her daughter-in-law to the mayor's nephew, especially as an inheritance is in doubt. The ladies kidnap, the men kidnap, the election campaign turns sour and the Baroness must capitulate. She takes revenge by falling into the mayor's arms.